ignition problems '82 gtsi....

So I'm driving around today and notice that a) the engine would sporadically go down on power (typically after going over some bumps), while at the same time the tach would drop to zero. After a couple of seconds the engine would start running again fine and the tach would stablize at the right rpm.

Felt to me like one bank was cutting out for a couple of seconds. Obviously, it's likely there's a loose or dirty connection somewhere as this seemed to happen when driving over bumps.

What is the tach driven off?

Does this sound like a failing digiplex?

The car is an '82 gtsi and it's bone stock in every regard. An engine out major was just performed w/in the last few months. I haven't pulled the caps/rotors yet. Hoping someone might have a suggestion or two before I go analyzing every single part in the ignition system.

Thanks!

 

Thank you gents - that's very helpful. Much appreciated. I'll dig into it tomorrow starting with a ground for the digi's, check the wiring to the reference sensors, check the sensors themselves. If that doesn't provide a solution I'll switch the digi's and try to do a little more diagnosis.

Thank you!

 

Thank you again fellas - problem solved. I:

a) cleaned the connections/contacts for the timing sensors,
b) cleaned the connections/contacts for the digiplexs,
c) installed the separate grounds for the digiplexs, and
d) cleaned a couple of ground connections in the vicinity.

Several of the contacts looked somewhat dusty and weathered. Some 600 wet/dry and a little WD40 where accessible certainly improved things, leaving a nice surface for good contact.

Great day for a drive.....