Hi guys. I recently did my upper and lower intake gaskets because of issues with the vehicle: http://www.grandprixforums.net/showthread.php?t=85912
Today I was letting the car warm up and the idle is still high. I replaced 3 vacuum lines that were leaking. Then the check engine light started flashing. The codes I got are:
P0123 (Throttle position sensor)
P0300 (Random Cylinder misfire)
P0452 (Fuel pressure sensor) *** I had a fuel line replaced at a shop from the tank and I'm wondering if they messed up or broke the sensor.
P0507 (Idle RPM higher than expected)
I sprayed and didn't find anymore vacuum leaks. I also knocked on the IAC while it was idling and the idle didn't change. Spark plugs and wires are 1.5 years old.
I've replaced the boost bypass valve and MAF in the past 4 months. I can only think that my coil packs might be bad (I had to replace one already).
I don't mind replacing the TPS, but obviously don't want to if that's not the issue.
Just looking for some advice from some of you who have more experience than me with this. Thanks!
