Need Help With My Idle!!!!, 98 Gt Auto, Please!!

[OBXWHTGT]

Hey yall, I have a 1998 Mustang GT automatic. Recently, once the engine has warmed up, when I come to a stop at say a red light, the idle will sometimes drop very low like 300 rpms and make the car shake a little. Its sounds like it really wants to cut off bad when it does this, but never actually has. I have a 2500rpm stall converter in it, could that be causing this, but its been in about 2 years and never had a problem. I had the check engine light come on, but it was for the same thing it always is, pressure inside the gas tank, I just havent gotten around to getting a new cap. Please let me know what you guys think, and if you have any possible ideas of what may be wrong. Thank You.

 

[caseypayne69]

Is it getting harder to crank from a cold start? Could be your Idle air control unit getting clogged up, or going bad. My was doing this and I just cleaned it with engine choke spray. and rubbed some gunk out. But my car would stay running if I keep my foot on the gas, but die if I let off.

 

[OBXWHTGT]

Thanks man, where is that control valve, ill give it a try, it still starts fine and idles fine, but once it gets hot its idles funny and wants to cut off. Let me know which part that is, because i dont really know where it its.

 

[caseypayne69]

If it idles fine after it starts then Its probably not the Idle air control. But thats plugged into the Plenum and reaches to the Cold air intake.