With the mid tester u can activate the ignition to run as if the engine was running, tach works, so u can bring it up to any rpm Without the high speed chip I was able to make the msd go as high as 15k, that's a sight on the test plug, so tapping the trans brake button, @8700 rpm I was able to make the ignition shut off with each tap. Think trans brake switch or tranny solenoid is bad. Jiggling wires while that high doesn't do anything. Dave SS/ea #1355