My vehicle started to accelerate on its own in heavy traffic going uphill on mountain roads. The braking system failed on the first several attempts to release the accelerator from its floored position. The vehicles safty backup systems failed in two different ways. First by not throwing a code that there was a malfunction( 3x in one and 1/2 hour trip)and secondly by failing to slow the engine when the malfunction occurred. Dealership can not find the issue and have suggested I pick up my vehicle and drive it until it occurs again.(which could possibly end up killing, myself, my child and anyone else who happens to be in the area of my out of control vehicle at the time) I have called GM and they are supposed to be following up on this today 1-20-09.