mikewilkinson

What is the main reason for back firing. when i've been driving in low rpms and i punch it, it backfires. my power band is between 1500-5500 and i've been around 1500 when i punch it. i have a 331 stroker that has efi and all msd ignition except a 6al box. you think i need the box? what could it be?

sprayed306

Bump......I have the same issues as you,i trieda msd and had no luck.[&o]

94StinkinLincoln

check your timing.
sounds like your running way to rich or way to lean
is it tuned?
whats your fuel pressure, any vac leaks, good plugs?
little more info needed