TPS issues are rare in my experience in the newer motors. They work a bit differently.

The idle is controlled by the ECU via the IAC. Sometimes the IAC can get gummed up with oil and junk from the PCV system. If it idles up normally on a cold start and then settles back down when its warm, and if the idle speed is pretty consistent, I'd look elsewhere though.

I have encountered a few problems with injectors though, and that might cause a rough idle. Pulling them and having them cleaned and balanced might not be a bad idea.

'97 4Runner, '06 F350, '86 4Runner, '05 WR450
http://home.4x4wire.com/erik