Power loss after warm-up

[mayagman]

I've noticed that I lose a significant amount of throttle response, power, and overall snap from the motor after the car has finished warming up. At first I thought it was simply because the transmission kept the engine at higher RPM, but now I notice this is not the case. At 2000-2500rpm cold, if I press the gas it immediately picks up and gets moving, when its warm, the acceleration feels muffled and dull. If I could have this cold power all the time, I would really love this car even more than I do now. My friend said he thought there was a TSB about this. Any ideas?

[SLAMMED_C]

Any check engine light??
Can you repeat this problem continuously?
The only thing that comes to mind is an o2 sensor... your car will run in a open loop while the car warms up.. taking readings form other sensors and overfueling.. then it will switch to closed loop and runs off the o2 sensor to adjust fuel... but that for sure would set off a check engine light....

[SpEeDy230]

I agree with SlammedC it does sound like an O2 sensor problem but it would set off the CEL

[mayagman]

I have a CEL on a Secondary Air Injection Malfunction... I think thats just an air pump that shoots air into the exhaust stream at warmup to make it pass emissions tests... not sure though. Could this be the problem?