August 17, 2005I have a 1987 Chevy Suburban with a 5.7L TBI 4X4 automatic trans. It has been running fine until recently. The temp rose above normal, then the motor lost power and strated running rough. I checked the timing and it was off. After resetting the timing, the temp stays normal, but when it hits normal operating temp, the engine starts missing and running rough with no power. I re-checked the timing under that condition and it was right on the money.
I have since replaced the coolant temp sensor, but still no change. The computer code reader shows no stored errors.
The O2 sensor has been replaced. replaced head gaskets and valve seals, thermostat, radiator cap about a year ago.
Any help on this problem would be greatly appreciated.. Thanks....