IROCmatt

my cars idling fast, about 1500 to 2000 rpm when u rev it up it takes a while to drop down slowly,
if i unplug the iac it makes no difference at all as if it does not work, i adjusted the tps and it made it run faster, untill i took battery off, and started it again. Its running sweet apart from this, what could it be????

ive lowered the throttle stop to get it ticking over where it is but wont go less. when i put into drive it drops to about 1200 if im lucky

MTXaudioSYSTM

id get a new iac. had the same thing happen to me today. except the iac came unplugged.

lucky14

Check for vaccum leaks....

IROCmatt

ive just fitted all new intake gaskets, im pretty sure its not an air leak, but may be, when u rev it up its takes a while for the revs to drop, if the iac is unplugged or plugged in it does not make the slightest bit of difference which makes me think its the problem

CaliChevyLover

vacuum leaks can come from vacuum hoses too...not just the manifold. are any of ur hoses fraying at the ends...

IROCmatt

ill have a look today, ive just done everything as its a new engine so im pretty sure its all alright

lucky14

More often then not when it all goes to pot... just after you did something.. it was something that you did or happened while doing what you just did.

I put new FI on my 383 then had a wierd idle... smoke tested it at the shop... #6 runner gasket was torn... just a reminder.. just beacuse they are new gaskets doesn't make them impervious to tears

Also check for ports your forgot to plug in etc.

Sounds like a vac. leak to me... but then again I am sitting on my **** watching G4 and Hockey and not sanding in front of you car.

If you don't have acces to a shop or a buddy that works at one who would let you borrow a smoke machine. Get a can of carb. cleaner and spray the runners and manifold down the idle should rise with the usage of the carb. cleaner if there is a leak.

If ok:

Check/Adjust. Throttle cables and Throttle body condition and stop adjustment

If ok:

reset the IAC and re-time to 6 BDC in D/R with PCM advance unplugged with warm engine.

If ok:

And still have an uneven idle we are venturing into more heavy things- PCM algorythim/sensor mapping issues, valve lash too loose/too tight, sticking shorted FI, bad pick up... etc... SOOOO check all of that stuff above this rambling line first...

Also remember..... I do this for a living... and my camaro still beats me like a rented mule everytime I do something to it... don't get frustrated... we will help guide you through it.