I am still hunting down the reason for the sluggish performance of the Q once the engine bay is heat soaked and was reading how to run the diagnostic test on the car. First off, I have no check engine lights, so will running the diagnostic tell me anything or is the only time it will spit out a fail code is when you have a check engine light? Any other tips to running the diagnostic tests on this car would be appreciated.

Thanks

It doesnt make any difference.. There are a couple codes (like KS) that will be thrown without the cel coming on...

Thanks Wes, that was what I was looking for. What is the difference between diagnostic I and II?

Diagnostic mode I lets you check the DTC (diagnostic trouble codes), mode II lets you check the o2 sensors (which is really a waste of time, trust me)

Thanks Wes.

So, with 80K, and no O2 sensor code, should I replace them anyway?

Heck, I thought Diag. mode ONE was to check the operation of the dash lights...and Diag. mode TWO was for everything else...Maybe I'm reading this all wrong...I don't understand alot in that FSM anyway...:-)

I went for an 83 mile run this morning, didn't even use a 1/4 tank, kicked it to 100mph 3 times...seems OK to me except for what I think is an slight exhause leak, but with the doors shut, I can hear it...:-)