Thread: Weird Idle. UGH

I'm having a weird idle lately and need some help and advise on finding whats wrong. Basicly when my car is cold or hot i rev the motor and my idle doesnt fully come back down down to 900-800 rpm's normal. It stays at 1400 rpm's, and if i slowly give it gas pass 2000 rpm's then let off the pedals it idle at 1900 then slowy comes back down to 1400 and stays there forever. I also notice if the idle is at 1400 rpm's and i floor the pedal down to the floor and release it quickly the rpm's drop to normal 900-800 idle??? and no codes off computer runs fine and idles only if I dont gas it slowly. please any help is greatly appreciated.

Jose C.

P.S As far as motor and mods

my motor is a sr20det non turbo lol seriously

w10 sr20det with no turbo runing it n/a
usdm 259cc,maf, and ecu and all sensors.
Stillen header.
Hotshot CAI.

sounds like a vacuum leak 2 me. get some carb cleaner and spray it where the gaskets are on the intake manifold, there is 3 and near any hoses and check if any vacuum hoses are cracked. if you spray carb cleaner and the idle goes up that means you have a leak in that area.

If it was a leak wouldnt i have a very low idle when start up and smelling rich??

If car is cold it shouldn't go down below 1400 rpm for a while. That's the cold idle control valve doing it's work. Usually it will stay like that for 3 minutes if your just idling



Nah it's probably too small to throw off the A/F ratios, but enough to mess up idle times

mines doesnt go down unless i floor the pedal to floor and release it quickly. then it goes down to 900-800.

So lets say i start the car up cold a few sec after it idles at 900-800 and it wont high idle at all by its self with out me doing anything.

If i rev it alittle it then goes to the high idle at 1400rpm. ??? lol

yea thats the same issue im having except mine only goes to around 1300 and it stays there for a bit an eventually comes back down..and i know for a fact its a vacuum leak. i just havent fixed it yet lol

mine doesnt go down, but eventually something will help me find the problem.lol

I can almost guarantee it's your coolant temperature sensor. Order the correct one (blue head for b14's, red head for b13's) - I have a writeup on the replacement on here. Obviously check vaccum leaks, check your timing, THEN throw the $20 at it to replace the part.

when you did the udsm sensor swap, did you swap your coolant temp sensor as well? When I did my swap, the same thing happend because I used the jdm sensor by accident.

i swap it from my b14 motor on to the sr20det. coolant temp must be good because fans are turning on and the car has a steady temp gauge nothing above the middle.

I just finish runing my codes and a hiding code i found was PO325 knock sensor malfunctioning. could this be it?? i reset the ecu. im going to see if it pops up tomorrow once i back home from work.