I have a 1999 Sunfire with the 2.2L OHV engine. I bought the car from my sister-inlaw as the head gasket blew and she couln't afford to repair it.

The following things were repaired:
New head gasket and head bolts.
New valve seals.
Valves all done over.
New spark plugs (Champion)
New upstream oxygen sensor (due to 0137 and 0141 codes)
New coolant temperature sensor ( rad fan was coming on too soon. Did not fix)

What is going on now:
Rad fan still coming on too soon which is due to the P0300 code that appeared.
Engine starts like the timing is advanced, and then runs rough, sputters, and babbles out the exhaust.
Noticed the catalytic converter hot. Maybe due to excess fuel getting into the exhaust.
Car has good power on the road. Pulls fine going up a hill.

What I've checked out since:
Pulled spark plugs and they looked good.
All spark plug wires checked out fine.
Ignition coils checked. 0.5 ohms for the primary (cold) Could not get readings for the secondaries.??
Had no way to check the fuel pressure.

What I suspect now:
Could it be a bad fuel pressure regulator?
Could it be a bad ICM?
IAC faulty/dirty?
Maybe a coil is really bad? (0301 appeared after I started the engine since)

I would appreciate some advice. Thanks.

have you checked for spark yet, actually visible? Should be easy to test because you have actually plug wires.

Compression test? You can rent one from auto zone.

If your going to go the replacement route start with the fuel filter as its the cheapest. If you have fuel in the vacuum line coming off the FPR then your FPR is dead.

If compression and spark are good next place I'd go is find someone who can test your fuel pressure.


-Chris

I checked the spark with a tester (pen type) and every one looked fine.
I also did a vacuum check and it checked out fine too.
Compression was good in all cylinders.
I didn't get any fuel in the vacuum line off the FBR.
Any more ideas?