Whats wrong

[z400master03]

My car runs very strong for the first about 10 minutes of startup, after that it seems like the power drops right off after the motor is warm. Why is this??I know heat robs power but it is quite a noticible difference..

 

[Synned]

I had this same problem. I would say that its the ECT sensor, but my problem turned out to be a faulty MAF sensor. It took me forever to figure out. I bought a used one for $30 and it hasn't done it since.

 

[HISSIN50]

The SN's are weaker when warm (IMHO). I would pull codes first (the CEL does not need to be on to have a code stored).

And as Synned said, cleaning the IAC, ECT and Maf are all good ideas on an SN. The former two can be tested at various temps to make sure they are within calibration specs. Bad O2's, a leaking EGR, etc can also cause issues once warm.

Good luck.