All the intakes are the same and all the exhausts are the same. What you are looking for is ONE or more that are far shorter than the others.
The worst case is worn exhaust lobes. They make for all kinde of missing. I had one one time on a chevy that was terrible and would hardly run. I took both intake and exhaust pushrods out of that particular cylinder and bent the spark electrode SHUT so it would not spark.. Upon starting it I was really surprised. It hardly had a miss in it. I ran it for a few weeks until I got time to put a new camshaft in it. 7 cyls was a lot better than trying to run with one real bad one.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />