jumpy idle
 

Ever since i swapped out my stock head for one with work done, pnp, valve job, milled .030", stg 2 cams, dual valve springs, ti retainers, adj cam gears, arp head studs, new valve seals, new head gasket, my idle has been messed up. I shouldn't actually say idle b/c it doesn't really idle.
When the car is at normal operating temperature the engine will rev up to 1200-1500rpm and bog down to 2,3,4,500rpm usually. It doesn't usually stall out, unless i have driven on the highway for 20-30 minutes. So after highway driving i have to adjust the idle screw just so it doesn't stall when i come to a stop before i can give it that ever-so-slight amount of gas so it doesn't stall.
I have a vafc and the sensor check says TPS is 4.45V @ closed throttle. I've reset and adjusted the TPS after i put on a 64mm bored b16 t/b with a new FITV (so the FITV is out of the question) But when i come to a stop and give it that "ever-so-slight" amount of gas the throttle reading on the vafc is 0.0 but clearly i am giving it gas b/c it steadies out the idle.
I pulled the IACV off and there was no build up on the screen. But can the IACV still be malfunctioning? I have replaced the PCV as well. Today i got out the old vacuum pressure guage. It jumped between 12-15 inches of vacuum at idle.
Any help is appreciated.

Sounds like it could be a vacuum leak, double check all those lines.

man I had this exact problem and could enver figure it out, possibly go get it tuned, thats what I was told andrew

its been dyno/wideband tuned with my VAFC. I figured the same thing but it didn't help at all.
I'm thinking maybe the o2. Anyone got a extra working 4 wire o2 i can borrow for a minute?

Well i have no CEL but i decided to check to see if it was throwing any codes. Sure enough code 41 Primary o2 sensor heater. So i replaced the o2, reset the ecu and checked for the code and it was still there. But still no CEL WTF?

definatly sounds like a vacuum leak

check coolant level , maybe u have a air bubble, air out your cooling system , this will cause a idle problem

or one of the sensors maybe faulty - tps or maf

and u need iacv , ecu needs to run properly

unstable idle
 

hi i have the same problem the engin wil rev up all buy itself at idle sit there at the light and people think im doing it 2 race or just because i have a noisy mufler so i pulled out my intake temp senswor and its just dangeling in the engin compartment but now it never revs up any more idles perfect