I know this thread is somewhat old but I was wondering if there has been any real conclusion for this problem. My 2003 5.7 L is having the same problems and I am the original owner of this truck. I had the lighting bolt come on once before and the dealer had to replace the Electronic Throttle Control (ETC) once before. Now the light is on again but only because I changed the ETC thinking this was my problem after my wife ran it out of gas having a bad sending unit on the fuel pump. I replaced the fuel pump and went to start it up and it backfired hard in the cat. The truck starts up every time with a very high rev and idles poorly after that. I have all kinds of codes pointing to the ETC and have even tried an re-manufactured PCM (Plug & Play) recommended by the Dealership with no change. Performed a Compression test with all cylinders showing 175 - 180 psi. Did a Leak down test showing one cylinder with 22 psi and the others between 11 -16 psi. I have decided to try another Dealer that has a DRB-111 scan tool...hoping they will get the PCM to communicate with the ETC and APS (Accelerator Positioning Sensor). Hoping to hear from them soon. Any ideas or help would be appreciated.
I just wanted to post some good news.... that my truck is finally fixed. I brought it to another Dealer and they solved my problem. To my embarrassment and $1450.00 later, I found out that you should never spray Throttle body cleaner directly into the ETC without first removing it from the intake manifold. Since the manifold is plastic on the 5.7L Hemi, this caused the truck to backfire hard which split the manifold resulting in a very bad idle and high rev condition when the starting the engine. Once the Dealer replaced the intake manifold it purred like a kitten.