When mine was new 1991 or so, the dealer replaced the coolant tempo sensor on the thermostat housing.
It can causes the ECM to think the coolant is 100% cold or 100% hot in the range of the sensor. If the ECM thinks the coolant is cold, it will run in warm-up mode which is really rich. It was also having a hard time starting.
Also, you said you checked the sensors. How about the sensor plugs and wires?
Tuesday, December 8th, 2009 AT 10:37 PM