5fse power loss after warm up? Options

[KaneO]

So i own a St204 (ZR) 5sfe Celica that looses some of its power after warming up for about 5-10mins. The thing has a whirling/ whining sound after it warms up also, I was told the timming belt was a little tight and it wasn't really anything to worry about. Did some research and found others that had the same problem. Most considered a O2 sensor to be the cause. But they claimed there's to blow smoke and mine doesn't.

Any help would be most appreciated =)

[199celica]

To make sure your dash lights work turn ur key to the on position without starting it all of the lights on the dash should come on. Well all of the optional lights if u have abs the abs light with come on so on and so fourth make sure they turn on. If not pull the cluster apart replace the lights that don't work. But i have had this whirling sound but mine is due to my alternator pulley going bad. I have not a clue why your car would lose powere though.