I have replaced my IAC, MAF, and O2 sensor but I still have that annoying up and down idle. Also after I drive it and then come to a stop the car idles really rough then dies. Anyone have any advice on how to fix my problem?
Sounds like a vacuum leak...check and replace all vacuum lines and make sure that the plastic "Y" that is between the boost solenoid and the turbo/wastegate actuator is the correct restrictor type and installed properly...
Also check the egr. Check at the base of the egr for leaks. Also check the metal tube the screws into the back of the intake. If either of those spots leak then they will provide you with a car that will not idle and will probably be running lean. Thus the dying out when you come to the stoplights. The car is really running alright probably but when you come to a stop the computer tries to compensate for what it thinks is a lean mixture by richening it way up when it doesn't really need it. This was the case with my car, but it might be a vac. leak somewere else on your car.
I have the Ultrachip 3.02, 30 psi injectors, 42 psi fuel pressure with vacuum line off. I think waco84gn is right though, because I broke the EGR pipe that connects the EGR valve to the intake manifold and so I plugged the EGR. I'm in the process of trying to find another pipe right now.