Hey guys I have the HEI with a "hi-po" module, cap, rotor and an accel super coil. It has been running fine, but the other night when leaving the local street races, it started misfiring above 4500rpm or so. It runs fine otherwise though. I am thinking that maybe the coil is going bad (dropping voltage at a higher RPM) or maybe the Module (God knows those things are unpredictable). Any Ideas?

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Black 89 IROC...355, Solid Crower Cam, TFS heads. 12.0 @ 120.3mph with a 1.9 60ft...all motor

 

If you are using the stock distributor system with high performance cap/coil/rotor combo your distributor pickup coil may have given up. They are covered with thin paper that goes brittle and is an easily overlooked component when troubleshooting.

If I misread your post.......then......nevermind.

 

I replaced the Magnetic pickup about 6 mos ago. Hopefully it is still fine.

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Black 89 IROC...355, Solid Crower Cam, TFS heads. 12.0 @ 120.3mph with a 1.9 60ft...all motor

 

Valve springs?

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"So many Mustangs, so little time..."
ICON Motorsports

 

GOD I HOPE NOT...it is possible, how do I check for broken ones? Wouldn't it start coming on earlier (the missing)?

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Black 89 IROC...355, Solid Crower Cam, TFS heads. 12.0 @ 120.3mph with a 1.9 60ft...all motor