Engine stalls when I let off the gas

[Chameleon]

I have a 99 XLT and it started doing this a couple weeks ago but went away, or so I thought. I am either coasting and take my foot off the gas and it dies or if I am at a stop sign.

I took off the IAC this afternoon and sprayed it down with Electric cleaner, the no residue kind and let it dry, it got a little better when coasting it would hover around 1,000 RPM and then drop like a rock. I have to slow down with my right foot on the gas and left foot on the brake.

Anything else I can try or should I just replace the IAC?

 

[fjanusas]

I would say just replace the IAC... It probably has worn itself a small groove in there and sticking... Did you try and a little WD40 before you stuck it back in after cleaning it?

 

[dogfriend]

Anything else I can try or should I just replace the IAC?

You could try using a throttle body / carb cleaner instead of electrical cleaner. Clean all of the carbon deposits inside both ports of the IAC.

If that doesn't work, then I would replace it. It definitely sounds like an IAC sticking to me.

 

[mawrazen]

Listen for a SUCKING sound under the hood while running. If you hear one, find your loose or damaged vacuum hose.

Also keep an eye out for Fluffy the cat! LOL

 

[Chameleon]

Thanks everyone!

I took the IAC of again and used some Seafoam Injector cleaner and let it soak for a few minutes, then sprayed the electrical cleaner in it, let it dry and then sprayed it again very thoroughly with the Electrical cleaner, let it dry again and put it back together, started it up and let it idle a little while with my foot keeping at 1,000. Took my foot of and it stayed there, revved it up and it went back to 1K and stayed. Shut it off and started it and it idles at 1K.

Thanks again for the help!

 

[dogfriend]

You may still want to look for a vacuum leak somewhere; 1000 rpm is a little high for the idle on a warm engine. Should be between 750 - 830 rpm in P or N with a warm engine. If its higher, it may be getting excess air from a vacuum leak. The IAC gasket is a possible source if it hasn't been replaced lately.

 

[Chameleon]

You may still want to look for a vacuum leak somewhere; 1000 rpm is a little high for the idle on a warm engine. Should be between 750 - 830 rpm in P or N with a warm engine. If its higher, it may be getting excess air from a vacuum leak. The IAC gasket is a possible source if it hasn't been replaced lately.

It wasn't warm then. After the test drive, it was idling lower.

Replace gaskets? NAH!!!