My car started lagging few weeks ago, it run's great for first 2 minutes when its cold. But after it warms up i can't floor it, first gear barley picks up speed and all the other gears don't pick up as they should. My car can't even get past 90mph unless i drop it into 4th and then it barley gets up.

I had check engine light for knock sensor and 2x o2 sensor codes. P0325, P0135, P0155. Bank 1 Sensor 1 and Bank 2 Sensor 2.

I replaced the 2 sensors with Denso premium sensors, replaced the knock sensor with the harness (new).

Drove 150 miles, but the car still lags. No more check engine light.



Any ideas? =/



Car is not shaky so it's not misfiring, i drove home doing 80 on the highway it felt just fine. It just doe not accelerate well.. feels like a 4 banger.... We also sprayed some wd40 around the engine looking for vacuum leaks but did not see any. There seems to be a tiny hissing sound tho, but that could be anything.


I have new fuel filter. The trans has been rebuilt few months ago. NGK spark plugs iridium or whatever the most expensive ones are called less than a year old. Air Filter and TB was cleaned 2 months ago when the trans was rebuilt. I got the K&N washable air filter.

Car has about 140k miles.

I have reset the ecu.

 

Just a long shot, did you reset the ecu?

 

My car did that a few months ago. I thought I cleaned out the MAF, TB, New knock Sensor and new plugs. Turned out my clutch was gone. Everytime I would floor it, the car would not move, also get RPM spikes as I shift.

 

yea clean the tb ..

 

Yeah, is the clutch slipping? Is TPS working properly? Clean MAF and TB?

 

Yeah, After changing my plugs, cleaning the tb, air filter to K&N, new KS, and clutch...OH MAN there was a big difference. The car launched like a rocket!!

 

My clutch is two months old i just rebuilt my trans. My air filter is clean, i got a new fuel filter. My spark plugs i put in this year, the most expensive NGK ones. TB and egr were cleaned 2 months ago. ECU was reset via obd 2 reader and once with the ecu screw.

 

Guys, I was with him helping him troubleshoot his Max.
For reference we replaced his clutch with an exedy stage 1 and fidanza flywheel back in April.

So, I think he needs coils but we didnt quite swap all of mine with all of his. His max attemps to stall in first gear unless you ride the clutch a bit until you get the car rolling a bit faster. we tried my new KS and new OEM harness, we replaced both O2 sensors and tried clearing the codes but the KS code remained unless it was the old school scanner we used. His Max still felt like the timing was extremely retarded which still leads me to believe its the KS but the thing is, I dont remember MY Maxima being THAT slow when I had a bad KS.

My money is on the coils

Oh also I ohmed out his 3 front injectors and 2 of them were above 14 ohms but I'm a little skeptical about the cheap multimeter our buddy loaned us that night lol

 

Cheap multimeter and the injectors would cause the car to shake if they were bad. Saw new coils on eGay for like 31$ a pop but i don't know how the quality is. Let's swap all of yours to test before i waste 180$.

 

If its just one injector, it wouldn't necessarily make the car shake a lot. Last time my injector was bad I didnt even know until I was actually driving.

 

guess ill have to install the carburetor mod.

 

I had one injector bad and had the symptoms described. Loss of power, shaking/threatening to stall when stopped, poor mileage.

 

I would try to switch maf sensors because a slowly dying maf could throw the o2 codes and make your car run like crap.Also sometimes the oil from the air filter could have gotten on it.You could also do the resistor mod for the knock sensor first to see if that improves things.Good luck.

 

I also mentioned MAF but he didnt think so

 

Well if maf was bad wouldn't it cause problems right away? My car runs good every morning for like 2 minutes. Same goes for the injectors?

 

turns out 3 bad fuel injectors. we just started unplugging some coils while the car was on and two rear ones seen to make no difference when unplugged or plugged in. Also one front one was bad as well.

 

there is a definite roughness to the engine when an injector has gone bad/stuck. i dealt with this problem with my old max. it was very apparent that something was wrong, besides the simple fact that the car was slower than it should be.


edit: just noticed you found your problem. nice. cars definitely tend to be slower when only running on 3 cylinders instead of six lol.

 

Damn I'm good

Oh of course there's roughness but I've had an injector(s) fail before and not be as obvious as some other times. His was running quite well for being on 3 cylinders! Thats Smartcar status right there lol

 

MAF... Switch it out with a friends Max if available. My 96 had a very simular problem 3 weeks ago. It ran great until it warmed up, then it would try to die at stop signs. I had to keep it running with my foot. Anyhow, I swapped out the MAF with a spare and VIOLA!!!! Runs like a champ again! Good Luck!!!




96 SE 5-speed Manual... Little bit here and there...

 

His MAF is good. We swapped them and he still had the same problem. We determined it was his injectors when we unplugged the rear coils on at a time and notice no change in the engine.

 

I wonder if the cleaning service RC Engineering provides for $24 an injector would fix this. New ones from the dealer are expensive and aftermarket ones go for around $60 according to RockAuto.

 

Knock sensor. That's the main reason why your car isn't performing right.

 

Dude... are you serious? lol


We have two known working knock sensors + OEM new harness that we tried and still the same issue. We already found the issue and its the rear injectors. The knock sensor wouldn't take away that much power regardless. His car is seriously slow lol like 90 hp slow


EDIT: Hmm, went back over mine and infowires post and I guess we didnt mention that we swapped knock sensors. my bad lol

 

When your injector was bad, what were some of the symptoms of the car? I think I might have a bad injector. I've been having a rough idle, bucking when the engine isn't warmed up, and a slight loss of power. I've already checked all the coils, maf, and ks. When I checked the injector harness, I got normal readings. I think the problem might be an injector that is stuck/clogged, thus, still giving correct readings, but malfunctioning.

 

it was mostly just a general roughness and slight loss of power. nothing too drastic.

go drive around and then disconnect a coilpack for each cylinder and drive it again (drive the car with 5 coil packs connected, testing each cylinder). If you disconnect a certain coilpack and then go drive around and the car still behaves in the exact same manner as it did with that coil pack plugged in, then you will have narrowed the problem down to that cylinder. so then you know either that coil pack is bad (or the spark plug itself is bad), or that injector is bad.

 

I tried testing the coils by switching all of them out with my girlfriend's I30 coils and still had the same problem, so I know it's not that. I don't have any CEL's (light or stored in ECU). The problem is really pronounced after the car has been sitting for a long period of time, like overnight. I get a really bad jerking/bucking when I first get going. The idle is slightly high (above 1000) and the engine feels rough. The problem tends to go away when the car warms up though. I checked the plugs too, which seemed fine. I'll try disconnecting the coils to see if I can narrow it down to the cylinder.

 

i wasn't suggesting coils were the problem, I saw that you said you already tested those.

for example, if an injector on cylinder 4 is bad, and you have all the coils connected it will run rough because cylinder 4 is not working correctly. if you then disconnected the coil for cylinder 1 (for example) the car would run even WORSE, because you would now have cylinders 1 and 4 not working (cylinder 1 because of the disconnected coil, and cylinder 4 because of the bad injector). This trend should continue if you tried coilpack 2 coilpack 3, etc. but when you get to coilpack 4, the car would NOT run any worse, because that cylinder is already "dead" i.e. disconnecting the coil on an already dead cylinder isn't going to make things run any rougher. by doing this, you can at least narrow it down to which cylinder (or cylinders) are having problems, so you don't have to replace all 6 injectors or anything like that.

 

Well said, that is exactly what we did in infowire's case

 

I tried disconnecting each of the coils and driving the car. All six that I disconnected definitely made the car run worse. There weren't any that didn't make a difference, which could help me narrow it down. It seems like the injector might not be completely dead, but clogged/malfunctioning. I'm not sure. Man, this has been a tough one to figure out...

 

My bad injector would come and go intermittently (I actually had this happen twice, two different injectors on the same 200,000 mile vehicle). sometimes the car would run great for weeks even months at a time with no issue. then i'd have a problem on and off for a couple days, and sometimes it would go away again and be fine for another week, few weeks, couple months, then it'd come back. finally i just changed out all 6

 

Hmm, I see. I would really like to confirm this as being an injector problem before buying new ones. Thanks for your help Nealoc187.

 

Ok so we replaced the rear 3 injectors with 3 brand new OEM ones as well as O-rings and all gaskets.

Car definitely runs better but still extremely laggy.
Swapped the following parts with my 95 to see if it would help after having done the injectors:
Mass Air Flow
Ignition coils
brand new 6 NGK Iridium spark plugs
cleaned/sanded temp sensor since it had corrosion

Even after all this, there was no change whatsoever. He did get a code for his O2 Sensor and its P0136 which is the one after the cat. I ran my car without that sensor for two years and never felt that lag so I believe that isn't the cause for the lag.

Only things left untested that we can think may cause trouble are:
Fuel pump
IACV
rear O2
maybe the cam sensor under the cam pulley?

Any suggestions?

We're running out of ideas

 

Just curious, does the car hard start when its cold?

 

Damn, those are some seriously ****ed up issues. Keep this updated as I have no ideas as to what the cause could be other than what you have already tried and ruled out. I doubt that the cam sensor would cause these issues but hey if you can test it go for it.

 

Starts up perfectly, in fact runs perfectly for the first 2-3 minutes until it warms. My car runs fine which is why we swapped all my parts onto his but geez, not even a sign of improvement.

Yea I'm also scratching my head here... I'm no master tech but in no way a noob when it comes to working on Maximas but this issue here has me a bit puzzled.

Here's another situation I thought of and I'm not sure if its possible. Lets say someone turned the **** on the ECU and left it turned in the wrong direction. Would that cause the car to be on safe mode?

Another note, we checked the ignition timing with OBDII scanner and its at 15 degrees flat. Anyone have any suggestion?

 

Just replaced coolant temp sensor and the last o2 sensor.. still same problem.

My IACV is making a ticking sound when car is in acc mode... idk if thats normal.

any ideas anyone? http://www.youtube.com/watch?feature...&v=h7xeyA2m7RA

 

My Under Drive Pulley (UDP) Unorthodox racing was loose.... torqued it to 140 lbs. Fixed my problem a bit more... but car still under powered. Going to replace one injector that had a broken plastic spray tip maybe it will help will report back.

My IACV is clicking still like in the video you can hear... http://www.youtube.com/watch?feature...&v=h7xeyA2m7RA i don't know if that's problem or not.

 

Seems that the 4th generation forum is either dead or just as clueless as infowire and I am with this situation. A couple of years back this thread would've been filled with replies instead of a few replies and half of them not related to the OP

On side note, infowire and I think one of the front injectors which IS missing the pintle cap could be causing poor spraying but we're unsure whether something like this would cause such lag. Anyone know?

 

Check for a clogged cat.

 

i have no cat... the cat is dead to me.



My exhaust was just done yesterday when i got the last o2 sensor installed. Problem is nothing exhaust related.