My car has a really rough idle and noone can explain it. Consumer guide has this to say about the 4th gen:
Can you guys explain this a little to me? Anyone have any experience with it? THe rough idle is bothering me. One guy on here said something to the effect of "A VQ with 103k miles will not be like brand new," but I don't want brand new, I want not-rougher-than-a-schoolbus. It makes the whole damn car vibrate.

 

check the obvious things first. Try pulling codes. If nothing, do general tune up -- plugs, fuel filter, oil change, air filter, etc

 

Two words: coil packs.

 

Acording to nissan bad coil packs will set off CEL. It is not bad unless it sets of a code. I have the same problem with my 99 maxima. And two things I have heard fromt he dealer ship, "its the nature of the beast" "it would set of a code".
The person made the most sense was jeff at maximum tuning. He told me it could be bad electronic engine mount. It does make sense.

 

The engine mount does not effect your idle. It can transmit normal engine vibrations into the chassis of your car if the electronic mount is locked up at it's stiffest point.

I've never heard or read of any electronic engine mounts failing for anybody on this board.

Your rough idle is most likely a weak coil pack, spark plug or fuel injector.

 

Then it should be a matter of time until the damm coil pack fails and i get a CEL and go back to nissan and yell at them for little while.

 

"Rough idle - Several problems (no-start, no A/C, rough running, etc.) can be traced to broken wires in the engine compartment where the harness bends near the right strut tower. (1995-97)"


I have never seen anyone say this on all my years reading and posting on hte org.


Clean your Throttle Body and IACV. Change your air filter and feul filter if you have not done so. WHen was the last time you gave it a tune up? Run some SeaFoam through the engine: http://forums.maxima.org/showthread.php?t=266435