Im willing to take any help i can get here. When i put my car in reverse or drive sometimes the RPMS go up and down till they level off. Once in a while it stalls(not very often). I also have a hesitation every once in a while while acclerating(usually between 2k-3k). Mind you these things dont seem to happen that often and they see to happen a lot more on a hot muggy day then a colder one. Anyway ive changed the plugs, coils, all o2's, pcv, fuel filter, ects, knock sensor, maf, new throttle cable, cleaned iacv twice, cleaned throttle body a million times, added a ground to my maf, and changed my evap canister. What else can possibly cause rpms to bounce occasionally and a jolt like feeling when accelerating? my mods are udp, gforce ecu, cai, y pipe, b pipe.......im an auto with 115k miles. Ive also had this problem with both ecu's so i know its not this one and i have no check engine light. Ive also had it hooked up to the consult II and my tps re-adjusted. The computer said everything looks ok. Any possible help or ideas will be appreciated...thanks

 

Just guessing here.... Fuel injectors? Leak in the intake? Cat?

 

The idle not being stable when you put it in gear is probably related to the IACV. Just because you cleaned it 1000000 tinmes doesn't mean it's working correctly. See if you can find a new or used one and replace it.

The jolt might be a misfire from a lazy injector or a coil pack. Try wrapping your coil packs lead to the plugs with black electrical tape. This will isolate the coil's plug lead from the valve cover better and give you less chance of the spark jumping to the valve cover before the charge gets to the plug itself.

 

well the idle on the car is perfect...it just maybe just once out of every 15 starts it likes to flutter before settling and on some occasions it just stall....what part of the coil do I tape? sorry i just didnt understand it but i will have to give it a shot this weekend

theres always a chance it could be my iacv but im not getting a code and ive already spent so much money trying to fix it that i dont really wanna go out and buy one only to find out it didnt work. plus i know the hesitation at times when im accelerating isnt cause by the iacv

 

I have the same car with the same miles and I was having similar problems recently after it started to get really hot a humid out. I just changed the engine coolant temp. sensor and that seemed to take care of it. I don't think you mentioned changing that in your thread. If not give it a shot...it's 25 bucks from autozone.

 

you might wanna check for vaccum leaks with all the things that you have changed, you might have negleted to tighten a bolt corectly. Check all the hoses that connect to your intake manifold. An abnormal hissing sound is ussually a good indication of a vaccum leak.

 

I have the same problem. It seems to be a common problem with the 4th gen maximas. It's irritating but I deal with it. it's only 2-3 months out of the 12. well at least where I live.
I have a manual. Sometimes when I try and start my car hesitates and dies. Then I have to restart. And I've found hesitation in between 2-3000 rpms. It's one reason I hate summer, my car sucks in the heat.
I have replaced the ECT sensor and nothing has changed. My guess is either the ignition or fuel pump.

 

i had the same problem. i bet its the crank angle sensor or some other sensor i cant quite think of right now(sorry).

 

yeah i changed that...actually today i lowered my iacv and it stopped the hesitation but now i have a problem with the car either almost stalling or stalling out at times when im stopped. Im getting closer

 

clean or replace your egr valve

 

heres what i learned today...if i raise the idle switch my low end and gear changing causes hesitation and rpm drops.....if i lower it too much it causes stalling and a weird feeling like the car is banging(although its not shifting nor are the rpms moving) when im cruising on the highway.....i finally found a spot in the middle where it drives fine but still fluctuates when you change to reverse or drive

this is weird

 

where is it and how do you know when its bad

 

Should be on the drivers side near the rear cylinder head at the transaxle end. It looks like a little flying saucer tank with a hose out of the cannon hooking up to your breather/intake. With engine cold lightly touch underneath the EGR pushing up on the diaphram. Should move up and down. If it takes a lot of effort to move replace it.

Don't quite know if this is your problem after your last post. But they do get clogged or go bad and symptoms are rough idling or just seems like it needs a slight tune up. Good luck.