I am a Ford Dealership Technician. I have an Uncle who has a driveability problem with his 94 Mustang GT. He is running a 347 "Stroker" small block with a Vortech Blower putting out about 8-10psi. When you accelerate hard you get a violent bucking and jerking, feels like the ignition is being shut off on and on. If you accelerate gradually up to wide open throttle the buck and jerk does not occur. The engine is fresh, less then 500 miles. He is running an MSD 6A ignition system. It has the Vortech variable boost/spark control sytstem. I believe he has at least 40# injectors in it and is running about 90 psi of fuel pressure at full boost. He does have the stock fuel rails on the car still. I have checked the rotor phase on the distributor as per MSD instructions and it is right on. Any suggestions would be appreciated.

 

What are your plugs gapped at? Factory spec is .052...with that you should run .032...you may be blowing out the spark.