so tonight i went to a movie, parked the car and went inside. came back out and tried to start it to find that it was incredibly hard to start. finally got it going to find my SES light (emmisions) had reset itself and idle was terrible. ive got to feather the throttle to get it to stay alive now .

Mechanically everyhting seemed fine. good oil pressure, drove fine, and im guessing its just in learning mode, however after driving back home from the theater (about 30 minutes) it STILL WONT IDLE.

What causes a car to do this? the battery didnt die because my radio presets were still there. any clue? mabye a bad o2 sensor? and how long will it stay in learning mode?

 

update: started this morning and idled fine, but still want to know why the computer would reset itself like that

 

You probably have a sensor on its last legs. The coolant temp sensor and MAF/IAT sensor will cause those symptoms.

 

Alright, cool. thanks. Anyway to check those sensors in isolation?

 

You really need a scanner so you can log the data to see when the problem shows up.