Problem revving engine. Skips to rev limiter

[Rebel79]

Ok this problem has been happening for a while now. It started after I did my fuel upgrade which consited of 30lb injectors, 6:1 FMU, and a Pro-M 80mm Mass Air Sensor.

Originally this was the problem: When under heavy throttle (3/4 or more) at 5,000 RPMs, the motor will suddenly shoot up to redline (6,250) and then backfire. The backfire was from the factory rev limiter shutting off every other injector.

After a week or so, the problem stopped happening in 1st gear, and continues to happen in every other gear. The only thing I can think of is my throttle spring may be wearing out. I seem to remember feeling the pedal go down when the engine RPM shot up.

Anyone have any other suggestions?

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1994 Mustang Cobra
308ci, Vortech S-trim 11#, ported GT-40 heads, E-303 cam, FMS 1 5/8 headers, BBK Offroad H-pipe, 2-chamber flows, and several other goodies.
Rebel Racing. Home of Bay Area Mustangs