whats wrong with my car???? so annoying
 

I've gone through all the scenarios in my head. Clutch, Knock Sensor, Fuel Filter, Plugs, Crankshaft sensor..................

Then I narrowed it cant be the fuel filter replaced that less than 10k ago with a 300ztt one. Plugs..are only about 25k old so those are an iffy idea.
Clutch problems I havent really experienced allot in my lifetime so its hard for me to tell if thats what the problem is or not......knock sensor idea....hmm I highly doubt it would be this noticeable.
Crankshaft sensor I dont even know those symptoms

Oh yeah and the problem is...............

When the car is cold things runs great.....and pulls hard....now when I mean cold I dont mean below the C its warmed up some just hasnt been running for longer than 15 mins.
After about 15 mins...which is about when I make it to the interstate, I'm heading down the on ramp.....and everyone is flying like a bat out of hell in the mornings...nothing new there. So I'm in second giving her the gusto.......and its like the car will pull.......then almost if its a mini backfire (no noise) just looses power for a brief second no rpm change...just like I was tapping the brakes while accelerating.......and it does this rapidly throughout the entire pull of second gear and into third. By fourth gear its gone.......but that gear provides very little power rpms rise so slowly.
I have no cel lights, and run 93 octane. Only bad thing that has recently while my friend was driving...he misshifted from 3rd to second....at about 80 but as soon as the clutch started to come out and the rpms we up he had the clutch back in.

So I was thinking maybe he toasted the clutch. However I have had this problem a little while....but its never been this bad...just now is it really noticeable.

Any ideas guys?

Have you had your coil packs tested?

Oh yeah forgot to mention those have less then 10k on them...replaced all six about 4 months back. :( Plus when they started going imeediate cel

Reasons I am thinking clutch is.......when its hot the engine compartment and the clutch has heated up this happens.......but not when its cold. I figure if it was the fuel filter.....it would happen when cold to.

weird I had the same problem with my max when I first bought it(96 se 5speed). It would hesitate exactly how you described. So I changed the fuel filter and plugs and I still had the same problem. Then I changed the ks, and the problem went away for good. I had a lot more power throughout the rpm range also. I actually went from a best of 15.5 @89 to a best of 14.7 @ 94 with i/y.

How many miles are on you max? Have you ever changed the ks?
-Paul

yeah the KS code is hidden.

oh well I'll check into the knock sensor then. Its a 99 but with all these highway miles.........I got..well..122k :(
So to check for the code can we use a normal obd2 scanner like they have at autozone??

You could do that, or you could still pull the codes from your ECU. KS will not trigger the CEL but will still throw the code if the KS is in fact faulty.

http://forums.maxima.org/showthread.php?t=104931

If only my 99 ecu had such a screw..lol. :(

wow, i never knew the 99's didn't have a screw

Yeah at least its not as big....as the 97 and 98 screws. I heard its there, just really really tiny and way back in the ecu..Anywho one more symptom that I just noticed.
Normally since I do mainly highway dirving I get about 450miles per tank. Granted it is a bit colder in winter but.......now I only get about 388 62 mile per tank reduction. Another sign of a bad knock sensor?

I have just over 100k on my Max and I still get about 420 per tank, I use either Premium or midgrade (along w/octane boost). When did yiur problem w/ks start?

i have the exact same problem on my on my 95 auto. your knock sensor is not working functionally after it's warmed up because the ECU will delay the ignition advance to stops the engine knock, therefore decreases engine power and killing gas mileage.

get yourself a $90 knock sensor on ebay. it is completely OEM. then follow http://www.motorvate.ca/mvp.php/507 for a simple installing then you are ready to go again. :)

I noticed in minor form a while back........and have just noticed that the car is getting less and less powerful. I knew it had to be allot less when my wife goes, wow for all that noise it sure doesnt go very fast...and it wasnt. lol :) Time to get up 90 bucks. Thanks for the help guys.

Here's your problem fellas:

The problem:
http://www.kcmaximas.org/forum/viewt...r=asc&start=15

The fix:
http://www.kcmaximas.org/forum/viewtopic.php?t=289


Dave

Hmm I dont think thats my issue. But here is a recent event. I got a cheveron gas card and have been running their 93 octane with techron ever since probably last three weeks. Even thought the problem was slightly apparent before.I notice it more now. Next thing. I dont think I'm running on five. I have run on five cylinders before when a coil went bad....and it runs like utter crap.........with no no no power and a shakey vibrating car. It will also make it idle funny. My car idles fine, and revs perfect not under load. However under load aka second gear or so the problem arises.
When I am in fourth I notice that it just doesnt have the gusto.....like it should. If I had dropped a cyl due to a bad injector the car would be shaking some and the engine running rough..but it doesnt do that sounds clear and good as day. Just doesnt have much power like the ecu is retarding the timing allot.
I'm going to go ahead and check the resistance on the fuel injectors this weekend. but doesnt the ecu monitor those>?? Wouldnt I get a cel light if one was malfunctioning

Howard's SE auto (the guy in the posts I attached) ran the same exact way. It idled fine, ran good until fully warmed, and usually experienced a miss in the higher gears and on the highway. Usually only under high load situations did the injector start to act up.

The ECU can't detect a failing injector. The ECU only monitors sensors to determine fuel delivery and such. It doesn't have the capability to scan injector performance.


Dave

Ok well I will for sure check it out then. Thanks :)

Ok another question I re read his post. Ok so his first post states from the get go. Hey number 4 cycl is down. If it was just a bad injector how did he know this?

On my old 90 maxima it went through total of 4 injectors (cylinder 2 and 4 i believe)

And all you have to do to find it is eithe check the resistance of the injectors to within specs or like mine idled bad so I would pull plugs till I saw no difference and that deteremined which one it was.

Sounds like a good idea........if only I could find someone small enough to fit under the hood closed while I'm on the interstate to do that :) I never have bad idle with this problem...not once.

Ok well checked everything out. I put in a bottle of injector cleaner just in case. I checked the front three injectors and they all read 12.3 ohms. I was suprised they were all so consitent. Of course now I have to take the manifold off some to get to the rears. Now assuming the rear are fine as well. I'll replace the knock sensor.
But could there be some valve damage after the mis shift?? I mean if the car is in nuetral and I have someone else rev it everything sounds just dandy and no issues. But like stated earlier under load and heat soak...it runs like crap. I mean as an example tonight a pesky caviler is messing with me.......in first gear he was right beside me and not until I shifted to second was I pulling. My wife was like your car feels so slow. Perhaps the misshift screwed up a piston ring and now one or more has terrible compresion. Heck I dont know so many freaking variables.
One thing for sure I'm taking that stupid frankencar cheap mid pipe out , tired of re epoxying this thing..........and for so much noise and the car in its current state I look like a retard taking off........god that car is loud but sure is hell slow.

I just thought of something. When I got the car back in 2002 at 79k I had to replace the spark plugs..no one in town had ngk's so I installed nippin denso platinums. So the plugs have about 43k on them. So I'm thinking new plugs would probably help as well. Sorry just venting my options here.

I have the same hiccup as you do. 1st gear is fine, but when I shift to 2nd, and I get up to somewhere between 2300 and 2700 RPM, the car sort of bucks a little bit. Same thing happens in 3rd gear, but not as bad. Unlike you, however, it happens more when its cold (it does still happen when its warm though)

I bet that whatever it is, its almost certainly to do with the fuel pump / injector pressure / fuel rails... I doubt its anything to do with plugs, coils, etc. But the car is 8 years old, and has over 100k miles, so it doesn't bother me too much. If it was American, it would be on its 2nd engine...

ks ks ks ks ks ks ks ks ks ks
You won't regret it. It's only $100.
-Paul

Yeah I'm gonna do a nice full maintenance on it. plugs, fuel filter, check the rear injectors, knock sensor replacement, and anything else. If that doesnt clear it up...Maybe I bent a valve.

UPDATE-
Well it appears as though the problem is now gone. I will see when I fill up today if it truly is. Couple days back I bought a bottle of lucas oil injector cleaner and piston top lubricator. Put in with about 3/4 tank left...ran it till today on e. I honestly havent noticed the problem recently.
I'm wondering if in the mornings when the car was cool I didnt notice it since the car runs so rich anyways but once warmed up and running leaner then when cold the effects of a clogged injector or a bad on became more apparent.
One thing for sure it pulls like never before. :)
I'm still gonna replace the knock sensor though. Thanks for everyones help