Ok thanks guys, I will try the throttle body reset first, which I have not done yet. I just replaced the fuel filter which had a lot of sludge in it and replaced the fuel pump, what a mess. Replaced the crankshaft position sensor with a new one again. Still the same results here. Rough running at low idle. I will reset the throttle body and will then check for the valve seal. Do I need to pull off the entire head to find a bad seal or can I replace the seal just by removing the valve cover? Removing the head is a big project and have done a ton to this monster so far.