0440thgt

Got a buddy with a 05GT 5 speed and when he pulls up to a red light, especially with the AC on, the idle speed falls to around 200-300 RPM and it kicks the check engine light on with a low idle speed fault.

Any ideas?

Nuke

Before doing anything else, I'd clean the TB and the MAF. Did he disconnect the battery recently? If so, it takes about 10-20 miles or so for the PCM's adaptive learning to settle things down.

0440thgt

No battery unhook recently.

He says that if he barely puts his foot on the throttle when pulling up to a light it will smooth out and wont' throw the code?

Nuke

Yeah, he's just manually creeping the idle up to where it should be. Try the TB and MAF cleaning, then lut us know wuz up.

mxg30

^^^ What Nuke said ^^^
Always always start with the simple solutions and save yourself headache and money. I certainly agree that this should easily cure your idle issue as this is a very common problem and as described above a common cure.