i have a 1978 mustang with a 347 stroker, it has a holley 600 cfm intake a cam and a weiand intake. i have put new plugs wires and cap on the car but it still seems to miss under acceleration. it has a new ICM. all it may need is a good tune but i have tried that and i cant gat anywhere, can anyone help me??
i had a Corvette that did the same thing and it was a bad plug. i would go that route first. its probably a spark issue but that depends on how old the motor and its components are. could be a valve leaking, bad lifter, gummed carb, etc.`
only time a car misses under acceleration is because timing is out. or the carb neeeds a complete rebuild. if you have a new holley 600 then yes its timing is out wont be by much but few mins with a timing light and will be sorted.
I'm with Jane...bad plug........Take a spray bottle with water and spray the headers. This will help you find the "cold" hole. Or, open the hood after dark and check for errant sparks on a running engine