I have a dually with 454.Has about 80,000 miles and won't run right.When under acceleration or load(hill)it misses BAD,sounds like an engine when you dump gas in the carb.I have had the carb rebuilt(by best in town)replaced fuel pump,plugs,wires,cap,rotor,coil filters and still no luck.$400 and nothing fixed.What am I missing,could it be the module?Bad distributor(if so does a small block work).I am about to replace the engine,but I am not even sure that that would fix it.Pleas help me.

A bad cam would somtimes act like you say.Do you have a good wrench in town to ck it?Does it back fire up top at all?(when under load)

Even "the best in town" can make a mistake every now and then... Make sure the plug wires aren't arcing anywhere. May want to try a compression test. Did you check for play in the distributor shaft?

I've had a lot of plug wire problems, even brand new wires. Also, I've had plenty of bad distributors.

It was plug wires.Thanks everyone.

Cool, glad you got it fixed.