first when i start the car rpms jump to 2000 then back down to like 900 then back up to normal warm up (14-1500). now i noticed when comming off high revs (above 2500) when i shift to nuetral they drop below normal idle to like 350-400 then back to idle (600). what could this be????

1. so i changed maf, no help, so its not that
2. plugs and coils changed 10k ago
3. IACV? i cleaned it a few months back and i have no SES light and no codes

what could be the problem here? thanx.

 

check for loose hoses that could cause a vacuum leak. also check your whole intake up to your TB. i didnt realize i had a really small leak and it caused me to stall

 

sounds to me like a vacuum leak also - are you MT or autotragic?

 

MT, also put my stock intake back (air box to tb only), but was getting symptoms before with berk as well. check and rechecked for leaks.

when rain clears up, ill have a freind start the car and listen to make sure iacv is working, i guess it either works or not, no inbetween. if it moves in/out it works right?, cant think of doing anything else.

also know a guy at nissan, maybe he'll plug in Consult II and that will tell me something?? but thats a last resort.

 

it's grime build-up around the butterfly inside the TB. when grim builds up, you lessen the air-space passing through the TB. since it's electronically calibrated to 625rpm (stock idle RPM), it will always snap back to that angle when you pop into neutral. since there is less air-space, the car drops to 2-300 RPM, and it feels like it's going to shut off. ECU overrides the low RPM and adjusts to 625, but only for that instance.

clean the butterfly, but that means you'll have to have the idle re-learned.

for the record, this happened to me and this solved my problem, which is why i'm confident it's the same for you. for me, it also sounded like a vaccum leak. for the life of me, i thought i was losing pressure somewhere, but alas, i was wrong.

 

checked and rechecked evrything, even went to dealer to plug in consult II and it shows nothing wrong, but i still have the problem!!! what to do???

 

I'm having a similiar problem, I'll post my progress maybe its the same thing

 

so you cleaned the throttle body and the butterfly valve and had the idle reset?

 

ok, today i changed the iacv....and ho help at ll, problem still there and is getting worse!!!!!!!!!!!!! HELP!!!!!!!!!!!!!!!!!!!

 

dude, in like 2 seconds i'm gonna fuking whip my **** out and slap you with it.

ANSWER THE FUKING QUESTION!!!!!!!!!!!!!!!!

DID YOU CLEAN THE THROTTLE FUKING BODY AND THE BUTTERFLY VALVE AND HAD THE IDLE RESET. HOW MANY TIMES DO I HAVE TO ASK BEFORE YOU ANSWER THE DAMN QUESTION.

EDIT: I'M GOING TO SAY THIS AGAIN. I'VE HAD THIS PROBLEM AND IT WAS BECAUSE THERE WAS GRIME BUILD UP ON THE BUTTERFLY VALVE. I CLEANED IT AND RESET THE IDLE AND THE PROBLEM WAS FIXED...