Service engine soon light on. 1999 Pontiac Grabd am SE
What could it be? We just replaced the crank
sensor, starter, alternator, fuel pressure regulatory,
battery was good still, front brakes, rear wheel
cylinder both. Replaced oil gasket with new also
change the oil with new oil and filter, replaced
coolant temp sensor, PCV Valve, the medal part that
is on the PCV valve. That runs from the PCV valve
towards the back of the engine. All new 4 tires. Still
a little rough idle, as well runs a little rough until it
warms up., o2 sensor not long ago, the one behind
the engine.