HEy Guys,,
I've read through all posts about IACV and MAF and whatever else. Can't find a definite answer...
Here is my problem - when car is warm, and I slow down to the stop light - drop into neutral - RPms dip down to about 250-300 and then come back to normal. Even worse, is when I start the car and it is warm - RPMs drop to almost 100, feels like its about to stall, and then get right up to normal. Few times it stalled twice in a row, and third time it was able to get up to normal.
Any ideas???
I have newev MAF - but I don't think its it, cause it drives fine.
New ignition coils and spark plugs. Clean air filter. Clean battery terminals.
If IACV would go - it would idle constantly out of range.

Got to drive to NJ this weekend, kinda worried it might die somewhere..
Any help would be appreciated...
Nick

 

same happens to my car, duno what it is

 

look into your cat, battery, alternator, and intake (dirty?). You might also want to consider an engine flush. Don't know what else it could be.

 

Thanks for your comments,

I cleanned intake, and it was fine for a while..
Battery seems OK, cleaned terminals yesterday. Starts up no prob.. No Battery lights.
I don't know how CAT would affect this. I got 110k miles on it, so its probably clogged, but why would it affect idle rpm..?

This sucks..

 

anyone else has issues with this?

 

This is most likely the cause of the throttle body. Have the TB checked out and ECU re-learned if any changes are made. A faulty MAF is something you'd first generally feel on the highway, when you realize revving past ~3500RPM is pretty much a nightmare.

Hah, just noticed you have a new MAF too. It's definitely your TB.

 

I agree....

 

Need updated software or TB needs a good cleaning.
Possible TPS malfunction, but rare.

 

Could some Seafoam correct this problem?

 

I used it twice in the past 15k miles. Cleaned TB about 20k ago and nothing was wrong then.. Car was reporgrammed about 4 months ago, with Timing bumped to 17 - no problems then. This just happened out of nowhere, few weeks ago, and I didn't do anything to the car before..
Strange.. I wonder if this happened to anyone on 02-03 model? Anything different on that TB. I am thinking of getting 03 Max..
Thanks for you replies.

 

I have 02 with same issue, cleaned out TB, reset ecu
Good as new!

 

did you reset ecu by disconnecting the battery terminal???

 

No that doesnt work, you can take it to a dealer to reset (easy for me I am a sales manager @ a nissan dealer) or i am sure i saw a thread on how to reset your ecu just look around!!

 

The reason why I asked was because I was having some of the same problems. My car just stall out of nowhere, sometimes. I don't know why it does it either. It doesn't do it that often. Maybe every week and a half to 2 weeks, possible longer. I don't know what the problem is either.

 

while a TB cleaning usually helps, this sounds like an IAC problem.

a failed or dirty IAC can be intermittent and the adaptive strategy for IAC trim only applied at certain times, mostly under steady conditions. i didnt write the engine mgmt maps for the vq30, but all of the programs ive seen, as well as aftermarket modifiers only use tables for target speed, load, ECT, and adaptive trim... theres a moment in between an IAC going from full decel to manifold vacuum decreasing and catching a stumble.


anyway, enough rambling... try a TB clean with IAC, let us know how it goes...

 

Wow, sounds way more then I know about engine management.
What do you mean by "TC clean with IAC"? I thought you can't clean IAC.
Thanks

 

technically you cant, but if youre using a mist based cleaner, like an induction service, at idle, much of it will go though the IAC. unfotunately an IAC can fail electrially, and mechanically (buildup). obviously the cleaner only takes care of one of them.

 

had a similar problem, cleaning the throttle body fixed it.