More IAC issues

[REGL8R]

Hey guys, thought I might have had my IAC right but no. Something weird is going on, I got IAC steady at 17 in gear, put it in park stays there. Now here is my issue when I put it back in gear it shoots up to like 40 (rpms go up) and snaps into gear. Do I have a vaccum leak? Only thing that looks loose is the vaccum going from the block directly into the middle of the intake. What is this part called?(not hose, piece that fits into intake)

I've searched but I can not find anyone who has had the same problem. Can anyone think of any solutions I just want this car to be able to drive daily.

TIA

 

[REGL8R]

I did some more searching and I see that different IACs in park and drive are normal. However, I still have a inconsistant idle meaning it fluctuates between 725 and 825. Is an exhaust leak a usual culprit of this, I have a very small one on my crossover.

Please help, I'm running out of ideas.

 

[cathan]

hey.....there could be several possibilities on your unsteady idle......how many miles on the car? Yes it's normal your IAC goes up when you put it in drive, I believe the part you are describing is the PCV valve.
Exhaust leaks are bad no matter where they are, fix those before you worry too much about your idle issue......these cars take patience to tune and you will go bonkers if you don't take your time!
good luck
Chris

 

[REGL8R]

The motor has 98000 on it but everything on it is new (gaskets, ported irons, poston headers, 009s, etc). We just got everything back together and starting to tune now that I got my SM. I'll fix the exhaust leak and see how that helps with the idle.

 

[REGL8R]

One more thing that I noticed, with the throttle blade screw all the way in the IAC counts are not at zero. Is there a possibility that my IAC has gone bad? 2 of the plastic pieces around the metal part on the actual plug are cracked.

 

[strikeeagle]

Well, with all the $$$ you've spent on heads and headers and so on, I guess a $30 IAC couldn't hurt...

 

[REGL8R]

LoL, very true. I guess its the price you pay for wanting to go fast.

 

[trbojo]

with your screw all the way in, you're also raising tps voltage, which makes the ecm see it as not at idle, so it won't try to compensate with the iac.

 

[REGL8R]

I understand that but with the screw al the way in and my tps range set at .42 IAC is still not at zero. I do not understand that.