All the name brands we used to rely on years ago seem to have gotten very bad, qualitywise. I won't go near a Fram oil filter for any reason, and am not all that crazy about Champion and AC Delco spark plugs any more. I just pulled a set of Champions out of the engine in my 27 that had very few miles on them and replaced them with NGK's. I can't tell you how much better the engine runs. Stronger all the way thorugh the rpm range and off idle there is no stumble at all.

Glad you found what was causing your problem.

Don