Depending on how Modded your car is, like mine, It could be a Clogged IAC, make sure your TPS is set right aswell. I've encountered that lots during my tuning stages and once its set perfect and your at good running temp, the problem could come back. Theres alot of temporary fixes. But doing everything right on the throttle body will ensure that none come back again. If you don't care for emissions delete vaccum lines and EGR you can find diagrams all over the place for that man
