My wifes car 2 weeks ago started to idle at 2500rpms, but it was sporadic.

I replaced her IAC and last night the TPS on her car thinking one of them was bad and causing the high idle. Neither worked.
I also sprayed out the TB to see if there was a carbon buildup and the plate wasnt closing properly.
I looked and didnt see any leaks in the vacuum lines.
The throttle cable isnt sticking...any ideas on what could be the problem?

I was thinking of replacing an O2 sensor. Her car is a 2003 Malibu with a 3.1Lv6. thanks for any ideas/help you can provide

Disconnect the battery for a while.