I've recently noticed a slight difference in the trucks performance. I opened it up on a nice isolalated country road and it would only get to 105 mph; Before it has easily pegged the speedometer. I'm going to change the fuel filter, tighten all boost coupling clamps and check the fuel pressure. My question is about the timing, is it possible for the timing to slip and has anyone had a problem with this? I have ordered a manual but it has not come in yet. Any help or suggestions are appreciated.