Pontiac Problems? Ask a Mechanic for Answers ASAP
Hello, my name is***** you for the question. On this engine this is caused by one of three things most of the time. It is either low fuel pressure fro a failing fuel pump, a leaking intake gasket, or a bad air flow meter. I always check the fuel pressure first. If that is fine then a smoke test of the intake is next. Re-torquing the bolts may help, and no, a leaking intake gasket will not always allow coolant to leak into the crankcase. If all of these are fine then the air flow meter may need to be replaced. I hope this helps. Please let me know if you need further assistance.
Sorry for the delay in getting back with you. A vacuum leak will cause all of these codes because it makes it impossible for the engine to properly calculate mixture and hold a good idle.
Pull the oil filler cap off at idle and see if there is a lot of suction. Most of the time if it is the intake it leaks on the bottom. What about the mass air flow sensor. Has it been tested?
These can fail all of a sudden due to their fine wire design. The wires that pick up air flow and temperature change can fail easily.