Pontiac Repair: Temperature Sensor, pontiac vibe, engine computer

Question
Hi,
We have a 2003 Pontiac Vibe that doesn't always start properly.  One day we went out to the car and started it.  Almost instantly it died and wouldn't start again.  The engine would turn over but didn't ignite.  We had the car towed and repaired.  The guy said that the teperature sensor was telling the car that it was way too hot so it would shut the engine off.  It did this even though the car had been sitting for a day.  After the sensor was changed we were still having the issues and about 6 months later it happened again.  A new service station told us it was the same problem however it still didn't fix it.  Also, we have noticed that the fan turns on and off constantly even if the car was just started.  I had heard that there may be another sensor that they are missing.  I hope that you have the answer to this because for some reason we are having issues with the repair shops.

Thank You,
Darren

Answer
Hi Darren:

from what your telling me here it sounds like it is indeed a tempature sensor related issue. If the engine cmputer things the engine is hot/overheating a few things happen it turns the cooling fan on to cool the engine off and also when the engine is hot the fuel trim into the engine is leaned way out (less fuel) colder it is the more fuel it needs. if the senor was changed and it still shows it hot when the engine is cold either there is a wiring issue to the sensor for the engine computer or possibly one of the grounds for the engine computer is bad or lastly a bad engine control module (computer) with out seeing it I can't tell you for sure what's going on it's just a guess. good luck :-)