First, let me say I appreciate everybody that has taken the time to give advise to me on this site. It has proven to be an invaluable tool to diagnose problems so thanks! Now to the problem: Engine has a slight hesitation at low throttle but runs like a scalded dog when you step on it. When I take my foot off the throttle, there is a random popping from the exhaust. It isn't a loud bang but a pop pop and it is random. It doesn't seem to do it when decelerating from a light load. I'm pretty sure it is not a vacuum leak and the car has new plugs. One thing I noticed when trying to get it timed in is that the vacuum advance on the distributor does not appear to be working. I have it plugged to manifold vacuum and I saw no change with it plugged off v/s plugged in. I rather doubt that has anything to do with the popping but just throwing that out there. Does this sound like a timing thing or what?