Ghost_54

iTrader: (13)

I have been reading threads all night long, and still have not found any true answer as to what may be going on with my car.

OK, here's what's going on: during normal driving, the car runs OK, but during heavier acceleration, it seems to be misfiring at around 4-5k rpms (mostly at just over 4200 range) to the point that I never hit the rev limiter (in the past the car would pull straight to 6200rpm before up shifting). It'll rev fine, but under power I'm getting a chugging like one of the cylinders isn't putting out power (misfiring). But do not throw any code (currently no SES light). My Max is an auto, the idle appears to be normal at 650-700rpm and performs like a champ under normal driving condition. The issue I have is under woot conditions be it in drive or drive3 the engine will pull very hard until it hit 4200rpm and then seem to bog/misfire straight up to 5500rpm or until I let off on the throttle.

I have had two codes: both were evap air leaks P0455 & P1448 (I don't think that would cause the misfire). My plugs have 20k on them. I only use premium gas. Oil level is good.

Items done since last summer:
- Plugs are New
- NWP spacers installed
- Coil were just reinstalled / not replaced. (But have had no codes to indicate one could be failing/failed).


Questions:
1. Is it possible that my thermostat needs to be changed? I've never replaced it so I don’t know if it's stuck in the open position (heat comes out of the vents before the car is up to temp. This means that coolant is circulating when the car is cold). If the car may not get up to full temp, the pre-cats may not get a chance to do their job... (But again I would of thought I would get an 02 sensor code or a per cat code).

2. Is it possible that I have a air leak? Be it somewhere on the IM or one of the plugs in place on the VIAS solenoid. ( I have a VIAS block plate)

3. Is it possible a bad fuel injector or leaking injector? (I have run a full can of Sea foam in a full tank and seen no difference).


I am puzzled as the car runs great and can reach into the high rpm if done by natural progression but if I woot the car even from 2000rpm as soon as I hit 4200rpm it seems to misfire or bog.

I thought perhaps MAF or 02 sensors but I have no drop in fuel economy so I am lost. ( and again have no codes)

Stormzusmc

iTrader: (17)

1 - probably not causing this. get a ir temp gun let your car idle and check the temps before and after the thermostat...should open around 170-180
tis easy to change no matter what

2 - could be, how long has the bop been installed? who did it? same with the spacers?
do you know how to check for vacuum leaks with brake cleaner?

3 - you could ohm out the injectors to see....

also check your oil
how many miles?
aftermarket exhaust /w or /wo original cat?
could be maf yes, but with the code you got maybe not... (our mafs suck though)

start with checking for vacuum leaks and testing your injectors, also do a compression test

Ghost_54

iTrader: (13)

Car has 219,000k I purchased at 93,000k and have never changed the the T stat ... One of the guys up here did the install of the block plate which has been in there for almost a year and never displayed this current condition. The spacers also install by a local member here as well as one step colder plugs was done over 9 months ago and again I have not ever displayed this current condition.

I have read many threads on how to check for leaks so that is one thing I need to do, to at least rule that out, so I will have to report back on that one.
Don't have an ohm meter so I would have to check for some assistance on getting a reading off the injectors. The oil level is good, oil even looks nice and clean, (well it should it was just changed a week ago but was still looking good even when the change was done. I do the changes at 5000k intervals.

Still have the original cats only change to the exhaust is a new B pipe over two years ago, removal of the resonator for straight through flow, and have a vibrant muffler now over two years old.

Yes our MAF suck, they tend to get blamed for everything, but still I have no issue getting well into the higher rpms and have no change in fuel economy. The misfire/blog occurs only in the mid 4000-5000 range ..

Stormzusmc

iTrader: (17)

start with the vacuum check
ohm meters are cheap, pick one up with a ir thermometer...and check those things
do a compression test as well
cat could be clogged...

Ghost_54

iTrader: (13)

I will do some more testing as you have indicated, but is it normal for this current condition to be present without having the SES light go off, and give some direction as to where the problems are stemming from?

Scottwax

iTrader: (8)

Could be IVT solenoid related too, but you should get a code for that.

Stormzusmc

iTrader: (17)

start with the obvious then work your way from there...you got an ses light, id knock that out first

Ghost_54

iTrader: (13)

Yes I also thought it felt like the variable timing being off, but like you believe I should get some kind of code especially if I was to continue to push the engine while it is misfiring/bogging

Ghost_54

iTrader: (13)

Currently no SES lights, so to me the obvious at the moment would be possible leak, or possible low compression, possible MAF relation, or a coil on its way out. Man I hate guessing

Stormzusmc

iTrader: (17)

Oh I see I misread - yeah check for the leak as you had those codes, check compression as well...all the stuff you already know to check you just gotta go down the line....

sontakke

You have two codes but no SES light? Is the bub gone?

Ghost_54

iTrader: (13)

No the SES light works just fine, I suppose I should clarify the codes that I have had in the past couple of weeks were the two I have listed above, and both point to the evap canister which is at the back of the car. Neither of them really have any relationship with the engine misfire/bogging at high RPM (well I don't think they have any relationship) both of these codes were cleared over a week ago and have not returned and if they return I will address the evap canister issues then.

So to sum up currently there is No SES light on ... and there are No stored codes pending.

Items to be checked and ruled out first:

- I am going to attempt to use some MAF Senor cleaner, to see if that corrects the issue.
- Possible swap in a borrowed MAF to see if the issue repeats its self.
- I also have 3 used coils, and can try swapping one at a time in and out to see If I can locate a possible week coil that is acting up.
- I currently have Auto-RX mixed in the oil crank case, which if the IVT has any blockage it should dissolve the containment/liquefy it so the filter should take care of that (it is just a slower process and requires some time to clean the internals).
- I am going to inspect and clean all the engine grounds to ensure the issue is not stemming from a bad ground.

So I will do these items first and report back, secondary issues to review would be,

- compression check
- have the pre cats checked .. and the main cat
- check the 02 sensors

As I stated the car runs really well, and pulls very well, its not until under woot that I get this ripple kind of misfire, so yes possible MAF issue or possible lazy coil that is acting up under the higher RPM stress.

sontakke

I think I will go with a strong double dose of fuel system cleaner in the gas tank especially if you have no misfire code stored. Techron in yellow lettering bottle or 3M or Gumout Regane or Redlight SI1 are possible candidates. You want strong system cleaner and not weak fuel injector cleaner. Any time I have a vehicle not giving me all of its rated horsepower, this is the first thing I try before doing anything else. Often times, within a single tank I get my performance back.

Ghost_54

iTrader: (13)

Don't think Techron (unless it is known by another name) is available up here in Ontario, (I'll have to check it out) ... I have seen Gumout Regan on the shelf so it may be worth reading the labels ... thank you for the input as it could be another solution.

Stormzusmc

iTrader: (17)

SEAFOAM!

Ghost_54

iTrader: (13)

Well ya we have lots of that up here

sontakke

Between Seafoam & Gumout Regane, go with the Regane for in tank cleaner. NAPA (in USA) carries 3M brand and they might be able to get you a bottle or two. Mind you it is expensive but worth it. I order it from shop3m website. Usually I use Techron or Regane but if that does not help, I open the 3M bottle. It has not yet disappointed me. I use 3M sparingly as it is my secret stash :-)

Stormzusmc

iTrader: (17)

weird im getting something like this now..but i got p0507.....i did the idle relearn and cleared the code, but still does it

mine is about 5K rpms and misses, but if i stay on it, it goes fine, then misses again....trouble shooting...F me...just got my car back

Ghost_54

iTrader: (13)

It is puzzling as I have no code to point to any particular sensor or area that is under performing. I trust you have unplugged your electric motor mount should you have one so as to not have it send a short at your ECM ... that code I believe is for the IACV which also tends to fry the ECU ... if your still throwing the code perhaps you need to replace that IACV module

Stormzusmc

iTrader: (17)

yeah im looking into it, but im also getting missing/popping at high rpms under load only
oh and code is back

gonna change plugs, pcv valve, inspect my throttle body, and go from there

Ghost_54

iTrader: (13)

Well I cleaned the MAF, and added 1/2 a can of seafoam to 1/2 tank of gas ... haven't taken the car to woot yet but seems pretty spunky up to just under 4000 rpm ... car is idling normal at 750rpm, have to drive it for a bit to allow the addition of the seafoam to get worked through and then I 'll test out into the higher rpm.

cmax1

Mine does this off and on also. Sort of like the engine bucks as the rpm climb. I know i have to change my rear valve cover that is causing oil to saturate the rear spark plugs, but do you think this may cause a possible problem? Maybe causing the coils to arch under load..

Ghost_54

iTrader: (13)

I changed my plugs and also replaced the rear valve cover last summer, (upgraded the valve cover to the 04 version) and mine did not display the current issues. I got possible have a bad coil/weak one, but under woot conditions the car should throw off a code for the misfiring coil, which of course it is not doing.

The MAF is one suspect, which I have cleaned to see if there is any improvement ... and air leak is yet another that I still have to do the testing on, especially along where the twin intake piping connects to the IM ... NWP spacer were also installed back in the summer without any issues but it is possible to develop a leak back there. The other suspect would be a clogged precat but then again it should have also thrown a code under woot.

cmax1

I thought under wot, the computer goes into a pre determined table that doesnt need the readings from the maf..

junglee Z

iTrader: (5)

i've been waiting for somone to run into a similar problem as me and here you are.. i have a 02 I35 and my car has the same symptoms as your car.. misfire and i had an evap code p1448.. i also have misfires randomly when car is in D and im stopped a red light.. i've had an intake, nwp spacers and block off plate, headers/y-pipe, test pipe (no cats at all) for sometime now and it ran perfect so i don't think that's where the problem is..
my guess is spark plugs or a bad coil(s)..
now this problem started when i threw in seafoam into my gas tank a while back (i've been having this problem for a couple thousand miles)
i had put seafoam (one whole bottle) into a full tank of gas and the misfire came when i came near to being empty in fuel..
in the past i also swapped out my MAF for a 01 maf and i know what a bad MAF does to the car and so i know it's not MAF related
spark plugs have been changed once before maybe 30,000 miles ago so maybe they need to be changed since i drive hard?
or it's a coil and my gut feeling is that it is a coil but i have no SES light regarding misfire.. so how do i know which one to replace?! (buying all 6 will be pricey)
i got a SES light for p1448, i reset the ecu, and it hasn't came back yet
but the misfire still continues. i also use premium gas
i will be reading your threads for any solutions you come up with.. but my personal advice would be not to use seafoam in the gas tank.. did anyone else have misfire after using seafoam?

Ghost_54

iTrader: (13)

I don't believe that seafoam has anything to do with causing a misfire, your P1448 is relate to a leak back evap canister system so I feel it is unrelated. My misfire/bogging is only under full throttle and not until I hit into the mid 4500rpm range. Possibly caused by a weak coil or an air leak and maybe a clog precat.

You mentioned that your misfire is occurring when your at a traffic light, I would suspect yours is more due to a bad coil or bad plugs and possible carbon build up. You could even have a bad fuel injector.

junglee Z

iTrader: (5)

is your misfire consistant? everytime on WOT? i get the misfire on WOT as well around 4500 rpm but it's not everytime.. and it's not everytime i get misfire at a traffic light either.. driving around the city letting the shifts happen between 2500-3500 is fine, no misfire.. and i did go WOT today a couple times.. 1 was fine and later during the day it misfired.. if i had a bad injector wouldn't i get misfire all the time? i'm just really confused.. i guess i should start with spark plugs? and do you have any tips on how to check which coil is causing misfire? how to test it?

also, could the gas cap not being tightened properly cause p1448 to come up? because after the ecu reset and tightening up gas cap the SES light hasn't came back

TunerMaxima3000

iTrader: (4)

Just going to throw out my initial thoughts after reading, because IMO you're off track a bit:

1. I doubt it's an intake leak, intake leaks traditionally cause problems at idle and low RPM.
The same goes for a Vacuum issue.
And the same goes for you MAFS in my experience.

2. Cat issue is very possible. There are a lot of ways to check,
- using a temp gauge at the front/rear of the cat when running. Temp should be higher at the rear, but not more than 200*F higher (or cat's working way too hard, if the temp was this different you'd likely smell it though - rotten eggs)

-The second way is to install a pressure gauge in the O2 sensor location just before the cat, run the engine about 2600RPM and watch pressure, it should not exceed about 20 PSI. Anything over 5-10 PSI is high, but not high enough to cause your issue.

3. Coolant Temp Sensor (there should be Resistance readings in the FSM and a testing procedure, sorry I am getting tired I'm not digging it out right now, but you want to check it at varying engine temps)

4. IACV - Same deal, use FSM testing procedures

5. Knock sensor. I don't know as much about the KS in the 3.5, but I can assure you this would be a priority check if I had this issue on my 3.0.

6. The lasts thought I had pop into my head were ECM/injectors/Variable intake/Tranny ECM and controls, all fairly unlikely based on your description.


I hope that helps and not hinders you. I recommend you test everything you mentioned as well, it never hurts to check. Also, have you run the codes anyways, even though you don't have a light?

And as far as Seafoam, I would NEVER trust that shyt in my car, I've heard way too many horror stories about it doing serious damage, etc., search for lawsuits.

Ghost_54

iTrader: (13)

Yes, a bad seal from the gas cap will trigger this code as well as P0455 ... The gas cap should always be the first thing to be check for these codes and if needed replace it as the cost is very about 10.00 ... after replacing the gas cap should the codes reappear then more investigation is needed, inspecting the evap canister and hoses for possible leaks.

Ghost_54

iTrader: (13)

Thank you for your observations, at the moment I am leaning more to a possible bad precat / damaged precat in particular the front precat. I had my emissions testing last spring and the passed with flying colors so a clogged cat although possible yet I can't see how it would clog slow quickly given the extremely low emission numbers I had just 9 months ago. I did have some heavy damage done to my front end back in Dec. where the Rad. both front lights, hood bumper skin and top Rad support all had to be replaced. I am wondering now if the front precat received some damage given all the pressure from the front end getting pushed in.

Emission test results from May 2009:
limit Reading Result

HC ppm 58 - 6 - PASS
CO % 0.32% - 0.00 - PASS
NO ppm 435 - 0 - PASS
RPM - 1476 - Valid
Dilution - 15.4 - Valid

Curb Idle Test

Limit Reading Result
HC ppm 150 - 2 - PASS
CO % 0.72% - 0.00 - PASS
NO ppm N/A - N/A - N/A
RPM - 1089 - Valid
Dilution - 15.4 - Valid

Damaged area's:


Area once repaired:


So before I start throwing money out there and chasing possible issues, I think a trip back to the repair shop is in order to rule out damaged front valve cover and damage to the front precat. Now they did have their mechanic's go over everything as they should to make sure all the electrical was in working order as well as the engine its self ... however they would not have pushed the engine to such extremes such as under wot conditions.

It is under these extreme conditions that the issue presents its self and yet throws no ECU codes, which is why I am puzzled

TunerMaxima3000

iTrader: (4)

From your pictures, precat problems look like a possibility. I would suspect that would be extremely apparent though when they removed everthing to do the repairs. Unless they ignored it.

Are you saying these issues presented themselves after the repairs? Or just recently?

The E-Test readings you presented aren't much use without the 'Limit' readings, those readings differ for every car, they are not generic.

It's possible to foul a cat in a short period of time. 9 months... approx 17,000km?
A bad injector/overfuelling, etc. can kill a cat pretty quick. Keep in mind though, most Cat's will last the life of the car if that engine is properly maintained, and all engine controls are working properly.

Anyways, it's not really worth chatting about right now, it's so easy, just test it, then we will know.

If you don't know anyone with a temp gun you can use, or the shop you did it at won't check it for free, you can run into Canadian Tire and buy one, use it, then return it (not the most honest thing, I know, but it works)

Ghost_54

iTrader: (13)

Hahaha on not the most honest thing ... And yes these issues were not present before the accident, so it was a thought to at least have it reviewed so I can ruled out any possible damage.

The limit reading is there it is the first number the second number is the reading of my car as an example

NO or NOX the limit for my car is 435 and my reading is at 0 and therefore - Pass

TunerMaxima3000

iTrader: (4)

HA my bad, I overlooked that completely. Yeah those are really good numbers.

Still seeking clarification: Did this problem start RIGHT after the repairs? Or did it just start recently (ie. you have been driving it for a while after the repairs were completed, then it started acting up)

I have to assume if it started RIGHT after, you would have just brought it back to them immediately.

Ghost_54

iTrader: (13)

Well I'll try to clarify it for you, I got the car back Jan. 14, 2011 and of course we were in the height of winter, roads were snow covered at best or extremely slippery so taking the car to wot condition was the least of concerns at that time. I did however take the car back once during the first week I had it because I felt the car was taking far to long to reach running temp. although the car did not perform abnormally just slow reaching where I was used to seeing it as far as the temp gauge goes. The first time the issue presented its self was about two weeks ago when because the road conditions were dry and I was merging onto the 401 decided to wot the car up to speed and as soon as I hit approx. 4200 rpm the issue displayed its self, what felt and sounded like a misfire/bogging so I let off on the gas, No SES displayed. Since this I have attempted wot conditions a couple of times and it has done the same thing (so it was not just a one time issue). So to be completely honest I have no way to gauge if the condition excited right from the day I got the car back or if it has developed over the past several weeks.

Hope that sums it up and adds a bit of clarity.

TunerMaxima3000

iTrader: (4)

Yes that clears it up I think. I have to say though, if the symptoms present themselves around 4200, I highly doubt it took you that long to check that. 4200 isn't that high, a minor wheelspin would exceed that, I have to suspect that unless you're the most cautions Canadian driver I've met, you have revved past that point.

I don't doubt though, that you only recently revved that high under WOT. So if you think that sounds accurate, that gives us a more specific scenario to base diagnostics on.
Try holding it in 2nd/3rd gear and let it rev past 4200 under 1/4-1/2 throttle. Does it still do it?


Either way, I'd definitely take it back to the shop that did the repairs and try to get them to check it out for free.
If you have the time, I'd check that cat before I take it to them.

Ghost_54

iTrader: (13)

That is just my point, first off the car is an automatic ... and yes I have been above 4200 rpm so I am not the safest driver out there. If I let the car naturally progress in speed and rpm's (naturally aspired) I can go straight through to 4300 rpm and then then the car will up shift to the next gear. Now if I was traveling at approx. 40 kmph and then wot the car once it reaches 4200 it acts up. Before the accident if I was to wot the car at 40 kmph it would continue to pull hard straight through to 6200 rpm before the up shift in gears, if that makes any sense to you.

TunerMaxima3000

iTrader: (4)

I know you're auto, I meant put it in '2' or '3' to keep it from up-shifting, then you can run it up higher in RPM without having the throttle over 1/2, keep it in that lower gear at higher speeds, so that you can run through the 4200-6400 RPM range WITHOUT having the car at WOT.
That will factor out most of the mechanical/physical components as potential issues.

And yes, Makes perfect sense. Let me think on it a bit, I'm just up now with my son for a feeding.
That does change the circumstances though, so we need to stop and re-asses.
I clearly just didn't fully understand your initial description. I read it again, and You did specify that at the end, I just didn't read it properly.


SOOO, We need to find out specifically what sensors are still active under WOT, and more specifically, what changes in the 4200-6400 RPM range with electronic controls and their control over the engine (ie. EGR opening, Variable Intake, Variable timing, transmission controls)

The good part is, most electronic controls are disregarded at WOT, so we can rule out a bunch of stuff, and if the symptoms are proven to only occur at WOT between 4200-6400, then we can also rule out pretty much every mechanical component. That includes your cat, plugs, coils, likely injectors (have to think about that), and obviously any physical damage with the engine internals.

Ghost_54

iTrader: (13)

It was suggested that a faulty coil/ weak coil that under normal driving conditions would appear to work just fine, but when thrown under the increase stress of wot that it then goes hay wire. When the car is in park or neutral the engine can rev quite nicely into the high rpms with out any hiccups. The issue only shows its self under full load.

TunerMaxima3000

iTrader: (4)

First 2 generic ideas I came up with were TPS and MAP (dont know if you even have one).
I have strong suspicions on the TPS, but there are further tests and specifics I need. Do you have someone close that would swap you TPS sensors just to try it?

Other testing to do in addition to high RPM run at half throttle:

1. WOT, all out from a stop, but use the gear selector to shift 1, 2, 3. (Shift yourself). Shift at redline. Observations - does it cough and sputter under these conditions? Are the symptoms different in any way from going WOT in `D`

2. WOT, then back off just a bit on the pedal (so you`re still loading the engine up hard, but not quite at WOT, lets say 7/8 throttle? Let it run through gears in `D`) Observations - does it cough and sputter under these conditions? Are the symptoms different in any way from going WOT in 'D'? Note shift point RPM, as it will be slightly lower

3. Same as above, but shift 'manually', observe any differences.



Also, how does the tranny shift, does it seem to be in good shape or does it jump around, lag in between shifts, slip, etc?

TunerMaxima3000

iTrader: (4)

I know you've likely considered and performed these types of tests while driving, as you mentioned in your OP somewhat. If you haven't done the specific checks above just do them, it's so we can diagnose better from the other end of a computer, I can't test drive it from here

And yes, there are a few things that could not cause issues until they're 'pushed to the max'. Injectors, fuel pump, fuel filter or other fuel issue comes to mind in that instance.
Electrical is one of them as well, you had a good idea to start with adding and cleaning grounds, that's always a good place to start when an electrical issue is suspected. Either way, you can spend half your life jumping from one 'possibility' to the other, and everyone on the forum including myself can throw out a bunch of things that it 'could be'.

But, That's just not the way to diagnose a problem, you'll end up spending a boatload of money and time before you fix anything. Slow and steady wins these types of races.