Recently installed a 70mm IPD plenum and throttle body on my 02 996tt. Performance wise, I noticed more mid range "pep". Later while on an aggressive drive with a Mustang gt500 I lost acceleration and my check engine light came on. Car went into limp mode so I shut it down, and back up again, it operated normal but check engine light still on.

Took it to independent shop and the obdII code P0638 Throttle Actuator Control Range/Performance (Bank 1) shows up. Çhecked all vacuum hoses, all ok.

Anyone have experience with this code? What does the "throttle actuator look like?

 

seen it happen... whos IPD and whos TB?

most probably a boost leak...
take the Y pipe off and pressure test at the TB... I bet you find some big leak...

 

Markski thanks for the reply! How far (safely) can the engine be lowered from the two bolts that attach to the engine mounts? I would like to check the back side of the rubber sleeves that attach the plunum. I suspect that that is where the leak is. Thanks a bunch! Still enjoying the heck out your exhaust!