I have a 2007 SLT. We recently went on a trip and the check engine light came on. My husband was driving and after the light came on, we were having problems taking off after a traffic light. He would press the accelerator and the engine would rev up like it was in neutral and the car would not move very fast. The car is still under the 3 year 30,000 mile warranty (barely with 25,000 miles) so I took it in today to a GMC dealer. The dealer said that there was a problem with an old code in the transmission which caused the light to come on. Would this code also cause the problem with the acceleration? A couple of other things we are experiencing is a rattle (in the morning) when you accelerate and the car seems noisier at higher speeds. We've already had the steering rack and steering pump replaced so I don't think it's those. Any suggestions? The garage couldn't find anything wrong with it all.