Magnifico

1992 5spd VE:

Well i posted on this a while ago but can't find the old thread unfortunately, hope I didn't miss any great replies. But i can explain the problem better now anyway. My car's been showing a few weird symptoms SOMETIMES, these symptoms almost always come together, I almost never get only one of them at a time:

-Car stalling at low speeds and especially at stops. The RPM will drop to stalling speed, sometimes the computer will recover the engine by revving it up to about 2 RPM, sometimes it wont. After an automatic rev, it will repeat the process over and over- RPM dropping to about 500, then going up to 2000, over and over, until it eventually stalls. If I manually rev it up while its doing this and give it lots of gas, it will not stall and will stop fluctuating for a while.

-High idle. When I'm having these problems, the idle is always at like 1200-1500. when these problems are gone, the idle is at 800.

-Jerky and slow acceleration. Accelerates, gets weak, picks up, gesrt weak, picks up.. etc.

-Stubborn acceleraetion at highway speeds. Never stalls at highway speeds.

What I have done so far:

-Taken it to 2 different mechanics. Neither of them could reproduce the problem, one of them even had it for 2 days and couldnt! At first I thought they may be incompetent, but my car WAS fine when i got it back... for about a day. This problem is off and on, but seems to be getting more consistent. Still, whenever I try to show someone, it never seems to happen =(. Annoying!

-fuel filter and air filter changed. Made no difference.

-Used fuel system cleaner. Made no difference.

-Got new spark plugs and tune-up about 3 months ago, wires tested ok at that point.

-Checked spark plug wire connections, seemed ok

Additional info:

-I don't hear any misfires or whining noises from engine. The car does lightly shake, most noticeable at idle, but it always has since i got it about a year and a half ago. The shaking isnt so bad that you notice it when your foot isnt on pedal, but you can see the seats visibally vibrate.
It seems to do this problem when engine is warm, i usually have to wait a few minutes before it will start doing it, and turning off the engine for a while usually makes it go away if its persistent. But I can't swear that it only happens while warm because it doesnt ALWAYS happen while warm. Sometimes it doesnt happen at all (those times are getting rarer though). i dont think ive ever had a problem while cold, but because of the off and on nature i think it may be misleading to say "only happens while warm". Doesn't seem to be a moisture problem, happens when its dry and sunny or raining. No check engine light, no codes.

Thats all I've got, browsing the forums a little I've read people asking about simialr problems, but never really saw any conclusions or people figuring out what the matter was. So if anyone had this problem and fixed it, I would appreciate a lot to know what it was! I can't do most things on my car myself except the simplest things, but those mechanics ask so much for diagostnics tests, so I'd at love to have an idea of what it may be or what its not. thanks

Jay93SE

I had a lot of the same problems. Have you had any hard starting issues? The reason I ask is because my fuel pump crapped out on saturday. I replaced it and it seems to have cured most of those issues. I think as far as the stalling, hard starting, and the up and down thing goes, that's probably a good place to start, assuming you've cleaned the TB, ruled out the MAF, etc.

Magnifico

oh yeah thanks, thats something i forgot to mention- i have no trouble starting, even after a stall.

Jay93SE

I didn't have trouble restarting after a stall either. The hard start's would happen once in a blue moon, and usually first thing in the morning.

internetautomar

iTrader: (30)

I'm betting on a sensor malfunction.
probably o2 or Coolant.
but I can't rule out tps.

Magnifico

hmm from what im reading those sensor malfunctions sound very possible, another thing ive decided on today is that this gets worse after driving the car for prolonged period (and turning off engine for 5-10 minutes ALWAYS helps for a while). By the time I've almost finished the 25 minute drive to or from school, it will be stumbling at almost every acceleration and wanting to stall on me at every stop. but during the first like 20 minutes the problem will only be at the occasional acceleration or stop.

internetautomar

iTrader: (30)

run the computer's diagnostics.

Magnifico

still not getting any codes =/. does that indicate that its more likely a fuel pump thing? i guess ill have to check the fuel pressure

Jeff92se

iTrader: (82)

1) Find old posts. Click the "search" button at the bottom of the screen. It should go to all your old posts
2) Sounds like your Auxillary Air Idle Control Valve.

Your going to need a FSM for this one. Or take it off and clean the carbon out of it. It could also be a clogged aux air control bypass hole in the TB. The little hole right in front of the throttle plate. You should be able to see it if you take off the accordian intake hose

eric93SE

iTrader: (1)

I didn't read your whole post but I'll list all the common things to look for.
1- MAFS connectors corroded or making poor contact.
2- Temperature sensor connector corroded
3- IACV plugged with carbon (after cleaning that out you should also replace the PCV valve).
4- Check for cracks in the ignition coils.
5- Check the resistace of the injector (11-14 ohms)
6- check that the alternator is fully charging the battery (test it by using a volt meter at the battery while the engine is idling and multiple accesories are on ex: lights w/high beams) should be at least 13.8 volts.

Magnifico

i examined that stuff Jeff and ya it was pretty disgusting, I can't SWEAR that it fixed the problem yet but I haven't seen it and my car definitely feels much better now either way so I'm hoping it did. I love my maxima again, at least for now, thanks for the help everyone! much appreciated!