Well, it looks at the engine temp and tells the car how much fuel to add/subtract to the ignition period. If this sensor is malfucntioning it can tell the car to use too much fuel (ie flood the car) or not to use enough fuel. This is why sometimes the car is fine on cold starts but wont start when warm, or vice versa.

 

Ahh gotcha, makes sense.

 

Well I replaced the sensor and that was not the problem. Towed it to my mechanic and it was........bad spark plugs. It seems when the new engine was put in the dealer used my old plugs. Thanks all for the help.

 

Why in the world would they use old spark plugs in a new engine?

 

That is something I will be asking the dealer....HOLTZ AUDI of Rochester.