So this 2001 six speed is on my last nerve! The problem is it revs up and down on its own, sometimes slow and other times fast to redline. So far we have replaced the APPS and the ECM with no luck. It dosent throw any codes when it dose this, the truck is not drivable because of this problem. Please tell me I'm not the only one that has run into this problem. One other thing is the coolant temp gauge pegs high when it dose it. Any thoughts???? thanks.