Hey guys. I have an 03 with the FM kit and ms3. Dynode by a professional here in Florida. The car runs very good and very strong. I'm having idle problem only with ac on. The higher I go with the ac fan the more problem with idle and if I turn the headlight on it's even worse. The rpm will go all over the place and then eventually the car dies. I cleaned the IAC and confirmed that its working (self test in tuner studio). I also changed the alternator with a new reman acdelco from rock auto. It seems that when I have more electric load it doesnt know how to idle. Please help with any suggestions. Thanks

 

I would recommend posting your tune and a log of this occurring in the megasquirt subsection of this forum, should be able to help.