My brother just installed MSD 6a Ignition and the Blaster 2 Coil with the easy install wiring harness. Now his tach is dropping off at around 4500 rpm's. Everything is normal up to this point, but right when it hits 4500 , it flickers and then drops back down (He does not have the rev limiter on his MSD). Just wondering if anyone could help.

P.S. He has an 89 formula 5 speed TPI

Thanks,
Jon

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350 TPI, K&N filter, Moroso cam, Airfoil, Accel fuel pressure regulator and gauge, Hooker headers, Flowmaster 3" catback ...more to come.

 

Yep, common problem.

Get the MSD "tach adapter" and wire it in, and the problem will be solved.