Ok guys, so I have a 2002 Maxima SE. A week or so ago it started shaking and missing very badly while I was with my girlfriend. (Figures right haha) anyways, I've done quite a bit to try and fix this problem. First of all, I have changed the spark plugs. The rubber circles failed on the gasket cover so they were full of oil. Cleaned them out, and replaced the plugs. Not a problem there. Missing wasn't as frequent and doesn't shake anymore. So today I cleaned my MAF and throttle body.. I also reset the ECU, and did the air intake re learn process. The cleaning helped the missing quite a bit, but the low idle, and misses are still there. I'm not sure where to go at this point... I'm hoping someone has suggestions.. I've worked hard to rebuild this car, would hate to see it go to waste.

 

ignition coils all gooodie?

http://boredmder.com/FSMs/Nissan/Maxima/2002/EC.pdf

follow the guide

 

I will try tomorrow or later this week. Never have enough time now a days haha

 

Do gen 6 valve covers when you get time

 

Would that help low idle? Or just preference?

 

Look for vacuum leaks. Especially if it's only at low idle.

 

Number of things could be wrong. Pull the codes, could be low or dirty oil, or caused by an excess build up in the cam actuators. Had the same problem after I pulled mine out of storage. Threw some seafoam through the oil, pulled both cam actuators off, fully cleaned them out. oil filter change. ALL stopped the rough idle. Mine as well was ONLY on idle, the codes that mine was throwing were P0300, P0021 and P0335. didn't change the cam sensor and it never came back.

 

I will check for vacuum leaks. The problem is I have no codes. The oil could possibly be the problem, I'm getting close to when I should do an oil change. I will do what you did this weekend if I can't find any vacuum leeks. Hopefully those help me.

 

No pending codes either? Do the Easy stuff first then take it from there.

 

Yeah, no pending codes, along with no actual codes. I'm gonna change the oil in a few minutes and we'll see. I'll let you know today if that changes anything. Maybe that's the problem and I've been overthinking the whole thing. Thanks for your help

 

Kudo's for the optimism, but highly doubt that an oil change is your culprit.

 

Well you win this one because it didn't, but hey, I got the oil change out of the way. Unfortunately it's still missing and is at low RPM's. My RPM's are at about 250 and stay there steady. When the car first starts it goes to 1000 RPM's then back down to 400. While in drive or reverse it gets down to 250.

 

Could be a fuel-related issue. These cars seem to be their happiest with premium gas (though it's only "recommended"). Try dumping a bottle of Techron cleaner into the gas tank and see if that helps.

 

Could try this.


Its free and worth a shot.

 

I have a bottle, I will put it in tomorrow and fill up. At least that's what the directions say. I'll stay premium from now on, but I had been using regular for a few weeks maybe a month and this didn't happen. But worth a shot. Thanks

 

I will try tonight I guess and let you know how that goes.

 

Unfortunately, that did nothing. In fact the problem may have gotten worse. Not too much, but now when it's in park it's just as low as when it's idle in drive. I'm gonna try that gasoline cleaner today and see how that goes.

 

looks like throttle body..or bad fuel pump (not getting enough fuel)

 

Not bad prices on those, do you know how to check that?

 

So I wanna give you a huge thank you. I put some fuel cleaner in along with premium gas and drove about 50 miles. The missing has stopped or is so little I can't notice it. I can't feel it either. Still have low RPM's though? Any suggestions?

 

Couple suggestions.

First off if you can get your hands on another MAF from a friend etc, its a common issue to have a 'cleaned' MAF improve things, but still be failing. Pop another one in and try it.

I personally had that situation, wound up buying the 2001 MAF with a temp sensor wire added in as the 2k2 ones are expensive, eventually got an OEM one from a wrecker that is still working fine.

Second I'd ask if you moved the TB butterfly by hand when cleaning, and if you properly did the Throttle valve closed position learning during the Idle air volume learning procedure.

I believe some people have had issues when moving butterfly by hand on drive by wire TB even after the Throttle closed procedure. However id be prone to explore the MAF route as it is a common issue.

 

I did move the TB butterfly by hand while cleaning. Ill try the procedure again. The MAF could be a little harder to find, not many Maxima's around here that I could borrow the MAF from. Unfortunately, today i accelerated very fast and when i went to park like 5 seconds later it started missing very badly and the RPM's were going anywhere from 200-450 very very fast. Car seemed like it was just gonna breakdown in the parking lot. Would like to get some more opinions before I take it to the shop. Should i replace the fuel pump and the vacuum hoses first?

 

You fuvked up moving the throttle valve, I'm afraid a new throttle body might be needed...

 

I don't think that's right.... All I did was spray it. And maybe clean out some grime. Other than that it was fine. Still moves fine the same when I opened it. Could it still be messed up?

 

I believe that to be a very debatable subject.

As i said before.... I have 'heard' (aka read posts) of that leading to TB replacement, but have also made that same mistake of moving butterfly myself without any long term detriment. I think it has the potential to damage the IACV or something along those lines, but i would still be prone to be optimistic and look for other causes due to the fact that the problem existed before the TB cleaning, and no new symptoms occurred after.

I asked the question because again i know from experience that i used to mess up the throttle valve closed procedure because i didnt read close enough, and kept ignition on for 3 secs like pedal relearn, instead of a quick on/off and believe this is a greater threat than messing up butterfly.

My money would still be on a MAF issue.

 

I actually went up to autozone yesterday, and they told me the didn't have a MAF I could try and then return.. Bummer really. I may have to travel a bit farther later this week to see if they have one. I'm going to guess its the MAF as well, because if I try to accelerate a little too fast it'll get to 2500 RPM's then kind of "skip" a few times then not change gears. I'll keep looking for a MAF when I get home today

 

So I went up yesterday and dropped my car off at the shop in hopes maybe they'd find the problem.. I was frustrated so I let them try and handle it. Well the dumb f***s couldn't "replicate the problem." You literally just turn it on. Once I get it back I'll try your guy's solutions that I haven't tried yet.

 

I'd guess they started it cold, and didnt bother to let it warm up. Sounds lazy to me. Does it idle smooth on a cold start?

 

It used to, then it started even when it was cold. That's why I took it up there, but they also checked the cat converter. Wasn't that. I was talking to the lady at the front desk and she said it might be the ignition coil pack(s). Since the 3rd cylinder was misfiring I replaced it. (Broke a bolt while tightening the intake down that was a pain the a**. ) Viola, no more shaking or misfiring. But still I'm getting pretty low RPM's. In park and neutral I'm at about 450 rpms, and in drive and reverse I am at about 200 RPM's. It doesn't really bother me much because the cars not shaking or misfiring but if I can fix it, I will. Thanks for all your help everyone, much appreciated. Anyone have suggestions on the low RPM's?

 

The thing which should fix the low rpm is the Idle air relearn.

I know you did perform it before, but if it were me I would do it again since you did some fixes, cleanses etc which probably fixed problems that may have been throwing it off the last time it was performed.

Follow the instructions closely which iirc includes things like having wheels turned straight, minimal electrical load (i put on ebrake to keep DRL's off) properly warmed up (I use scanner to read coolant temp rather than temp guage) no MIL codes etc. If it doesnt fix the Idle then you do have another issue to start tracing down such as vacuum leak.

 

Ok I'll follow your advice and do it again. I have a scanner as well, can I ask where the engine temp is located? I'm not sure if it's different for others scanners. I can't imagine it is. Thanks for your help

 

If your scanner can read the ECU's datastream and not just codes, it will most likely be labelled ECT. If not, a 10 min drive should be more than sufficient to be fully warmed.