Hi all. Would be quite grateful for some assistance. Stu--you still around? Bone stock 79 Rx7 12a points ignition. Runs great but tach has just mysteriously started bouncing erratically from 2 grand to 7 etc back and forth while the car sits at idle. car has been in storage for awhile if that matters. Pulled the battery and alternator and had them checked today. Replaced points, cap, rotor, plugs, and coils...checked all connections for coils, dizzy, battery, and plug wires. Replacing plug wires tomorrow. What else could it be? It seems like it would be simple so I have done the simple things that are the usual suspects--especially the trailing coil. Any ideas? Oh--and now that I replaced the points, any tips on how to set them? Going to hop on faxed.ca and check out the manual. All other ideas are greatly appreciated. Thanks!

 

I personally would check the grounds. They have been known to do very random and weird issues when the grounds corrode from age.

 

It might be the voltmeter activating.

 

Which would mean check relay is messing up, if I recall correctly.

 

its either the choke and check relay, or the points. if the ignition misfires, it'll register on the tach, and it will misfire if the points are bad