Just recently went to Jennings Florida to race Vintage Motorcycles and had a backfire under load while pulling a trailer. I did have it in drive.

I had though it was a vacume line and as it turned out it was a sparkplug wire arching in the exhaust manifold, or so I thought.

I ran well to Orlando and Back with a couple of cough here and there. I didn't think much of it.

Until my wife went to Ohio this weekend and it backfired quite a lot of the way. She was lugging the motor (302) in overdrive (AOD transmission).

I still suspect a vacume leak and lugging the motor it's pulling most of the vacume causing the emmisions to backfire.

I am not taking it to a Mechanic to replace pieces until it is better. Something I can do. I have restored a few cars in my time and am a Motorcycle Mechanic/racer. I do most of the work on my Vehicles myself.

Any pointers as to the problem will be much appreciated. I need to have piece of mind while my wife uses this van for dog shows. (The biggest reason I got it.) It's not pretty but doesn't need to be.

New rotor cap, new rotor, new plug wires, rebuilt carb (2bbl), have new coil but not installed yet, new plugs, new pcv valve, new air filter, new crank case filter, fresh oil change.

THIA

Eric