Hello & Welcome to JA,
This problem can be cause by a fault of communications in the Throttle Actuator Control & GM has released an update PCM calibration to address the problem.I am going to get that information & send it to you.
Be right back.
This bulletin is being revised to delete the 2007 model year and engines except for the 2007 MD 3500/4500 Tilt Cab Models. Please discard Corporate Bulletin Number 06-06-04-042A (Section 06 -- Engine/Propulsion System).
Some customers may experience engine operation in the Reduced Engine Power mode, an MIL/SES light on and DTCs P2108, P1516, and U0107 set.
This condition may be caused by an error in the TAC Module communication software.
Reprogram the PCM with the latest calibrations if the above concern is encountered. An updated PCM calibration is now available to address this concern. This calibration, or any that follow, is designed to address this concern. Refer to Service Programming System (SPS) using the appropriate Service Information (SI) procedures. The new PCM calibrations will be available to dealerships as part of TIS2000 incremental satellite update version 8.5, which was broadcast to dealers on 08/20/2006. For the dealerships that use CDs, the CD version will be 8.5 for 2006, which will be mailed 08/24/2006. As always, make sure your Tech 2® is updated with the latest software version.
Is this saying take it to the dealer?