VDO tach has gone crazy

[six is enough]

Went to the track two weeks ago car ran great. This weekend car would spool at the line as normal but about 60 foot out car would start popping and missing, let off and get back on it would just fall on its face. Found a loose plug but this did not fix the problem. The next day at the track same problem, then the aftermarket tach started jumping all over the place. Would show idle at 850 and would jump to 9 grand and back and forth and then would show idle as it should for a moment and then act up again. I am running the translator plus with the extender extreme with a rev limit set a 6000. Is this why the car would not pull it did seem like it would hit the rev limit and shut off and then back on. What could be the problem. Unpluged the tach and car was better but still would miss and pop at the shifts. Car was still about a second slower than normal. I dont know where to start looking. Any ideas?

 

[6SENSE]

I'll take a shot at it. Maybe ignition modules dying on you. That would cause your popping and missing/performance issue, plus isnt that where the tach signal comes from on our cars?
In my experience Ive dealt with popping/missing associated with coil pack, module, and bad plug wires (or switched plug wires ). The fact that youve got this tach thing that started up at the same time may be a lead/clue.
Correct me if Im off guys, I know someone will chime in who knows for sure.