St4ngGt

A couple days ago I posted a question about the change in idle in my car and the RPMs falling really slow. I cleaned the IAC like most people said, fixed the cracked tubing for the AC, and unpluged the battery. The problem is still the same and was wondering if anyone has any other ideas. Should I just buy a new IAC?

cliffyk

Can you be more specific about "the change in idle in my car", and "RPMs falling really slow"--it is normal for the revs to hang at 1200 or so 'til the car actually stops moving, and for the engine speed to fall a bit sluggishly between shifts (a "bit", not not a lot, or increase). [/align][/align]You can thank the Government for all of that as it makes your car's bad-boy emissions 0.000001% less than they would be otherwise--if it's more than this then there's a problem, if not then search for "IAC mod" here and on other boards and you may be able to find deliverance...[/align]

St4ngGt

Whenever I shift, the rpms hang for a second at the same speed and then fall slowly until i shift into another gear. Same thing when I start up the car. It will hang at higher rpms and fall really slow, or slower than normal.

It also raises the rpms when i turn on the air conditioning.

kylebgt

Raising when the ac goes on is normal and happens in all cars. My idle used to drop all the way down to 300 or so rpms and sometimes stall the car when I would put it in nuetral at cruising speeds. The Idle air control unit takes over when you put your car in nuetral. When I cleaned mine it just made it worse. It wasnt until I bought a brand new iac that the problem went away. Thats what I recommend you do.

St4ngGt

The main problem is that the rpms dont fall when I shift or start the car. The AC was just something else I noticed that might have to do with it but i should still just buy a new IAC?

kylebgt

How long does it take for the rpms to fall? say you are cruising and put it in nuetral, if it takes like 3-5 seconds to fall down to around 1k than you're normal. If your idle never drops and stays at 2k no matter how long than you have a problem.

St4ngGt

Its probably around 3-5 and then falls slowly, but this is way slower than before.

NeoTokyo

This thread I started might be a good thread for you to read through.
https://mustangforums.com/m_3145889/tm.htm
I know its for the sixers but its based off of the Mach1 restriction mod.

Its worthwhile reading with real world results and test peices.

cliffyk

If it's falling more slowly than it used to then I'd wager the IAC is stcky on closing--you've said you cleaned it, however I'd clean it again and then get a new unit if that fails to speed things up...