1993 E 350 club wagon, 460 gas engine with a Banks kit .
nothing too sexy here just headers and exhaust and I don't know if they messed with the computer or not. Anyway it goes like a scalded dog and I love it but, has developed a funny little "stumble" at no particular interval. Sometimes at an idle, sometimes at cruising speed, sometimes under load etc It never tries to stall just a little stumble. I have eliminated fuel supply as an issue so I am sure its electronic or ignition ,has anyone had similar issues that could lead me in the right direction? "things left to themselves tend to get worse" since I spend a fair amount of time on road trips I'd like to fix it in my driveway

Phil