[SoTxButler]

I had a situation very similar to yours. Mine is an EFI motor, but the popping is what is similar.

Everyone who listened to the car told me it was an exhaust leak. I even moved the Oxygen sensor forward of the slip fit headers in an effort to zero in on the air leak issue since the wide band was giving me bad numbers (rich to lean and vice versa).

Finally took out the injectors and found one on the bank that was popping with some trash in it. Changed the injector...no more popping. It fooled everyone.

Now, my thought is that you may have a fuel problem in addition to a possible exhaust leak. The stumbling upon acceleration after you have let off suggests to me that it is fuel.

Anyway, this is what happened to me. Believe me, some VERY knowledgeable people swore my problem was an exhaust leak.

Hope you can fix this problem...mine drove me crazy.