Pontiac Repair: rough idle & excelleration, 95 sunfire, head gasket problems, coolant leaks

Question
i have a 95 sunfire w/2.2 ltr. when cold the car idles rough and excellerates as if it were a standard in to high a gear even though the car is an automatic,( trans is fine im just refering to engine performance). when car warms up it runs alot better but still has a noticeble miss. it doesnt over heat and there is no water in oil or visa-versa. i have replaced the plugs, o2 sensor, air and fuel filter, and also run bars in it after being told it was a pin hole leak in the head gasket, all with no real change in the performance. the car is regularly serviced ( oilchanges ect...)but i cant seem to nail this problem down. i had a diagnostic computer hooked up to it which read as if there was no prob even though it was obviously running rough. please help im at my wits end, thank you, chad

Answer
Sounds like you have a bad temperature sensor Chad. There are two temp sensors, one for the guage or light on the dashboard and one that goes to the computer so that it can adjust air/fuel and spark, etc. as the motor heats up. Have the diagnostic scanner hooked back up and watch the temp reading to see if it comes up to the proper reading. As a final side note bars leak may be a highly pushed product for coolant leaks but it's really great at cloging up systems to the point of system failure and it isn't designed for head gasket problems anyway. Hope this helps and good luck :)