Another idle issue thread (high idle)

[9746Cobra]

My '97 Cobra idles at 750rpm with AC on or off.

My '96 Cobra idles at 900rpm AC on or off.

I tried resetting KAM, cleaned the throttle body, adjusting the throttle stop screw, cleaned the IAC (Which runs at about 35% like it should), and made a restrictor gasket for the IAC out of alluminum.

I started the restrictor gasket at 5/32". Car idled great at 750rpm, but when the AC was turned on, it would nearly stall before recovering. So I opened up the hole to 6/32". Better, but idle went up to 800rpm, and would still almost stall when AC was first turned on. Went to 7/32". Car didn't want to stall when AC turned on, but idle climbed back up to 900rpm, right back where I started.

I gave up at that point because restricting air to the IAC was just making the computer open it more.

If I disconnect the IAC, the car dies immediatly, ruling out a vaccum leak.

How the heck can I get the idle down from 900rpm to 750rpm?

9746C

 

[COBRASVT]

900 isn't bad....most with issues are 1200 - 2000.

What's the voltage on the IAC? Middle wire btw...

 

[PSUCOBRA96]

800-900 really isnt bad

 

[albino96]

Mine idles at like 1500 after I stop completely fro like 5-10 seconds before falling down to 900 or so, not sure why. I'd actually say 8-900 isn't bad.

 

[Birdinator]

My '97 Cobra idles at 750rpm with AC on or off.

My '96 Cobra idles at 900rpm AC on or off.

I tried resetting KAM, cleaned the throttle body, adjusting the throttle stop screw, cleaned the IAC (Which runs at about 35% like it should), and made a restrictor gasket for the IAC out of alluminum.

I started the restrictor gasket at 5/32". Car idled great at 750rpm, but when the AC was turned on, it would nearly stall before recovering. So I opened up the hole to 6/32". Better, but idle went up to 800rpm, and would still almost stall when AC was first turned on. Went to 7/32". Car didn't want to stall when AC turned on, but idle climbed back up to 900rpm, right back where I started.

I gave up at that point because restricting air to the IAC was just making the computer open it more.

If I disconnect the IAC, the car dies immediatly, ruling out a vaccum leak.

How the heck can I get the idle down from 900rpm to 750rpm?

9746C

Did you check your EGR valve? If it is stuck open, that could be dumping exhaust into the intake manifold.

 

[SVTStrikesBack]

Is there any benifit to having the idle higher or lower, other than just saving gas?

 

[SVT-98-]

When I first bought my cobra it had high idle issues, dealer changed the TPS, IMRC's, computer. In the end they changed the throttle body, and its been perfect for the last 70K.

 

[Dixie96Cobra]

Is there any benifit to having the idle higher or lower, other than just saving gas?

I think it's more annoying than anything. Something obviously isn't running right, and that annoys me......my .02

 

[FATPAUL]

^Yep i hated it

 

[9746Cobra]

The '97 Cobra idles around 725 rpm, the '96 idles at about 850-875.

If thats not considered bad then I'll leave it alone.

Thanks guys!