MY car has been running a bit rough lately, and I noticed a misfire... the misfire is in sync with my bouncing tach... when the tach bounces, it bounces up, not down, when it does, the car misfires. Im going to perform a tune-up soon, but Im sure that wont fix my bouncing tach. Im guessing loose connection, where should I start?

92 Z28 - TPI Stock.

 

Ingnition module (in the distributor). Check for burnt/arcing spark plug wires also - arcing can make the tach bounce. The module could be going out, or the connection is loose. Replacing an old one is always a good idea with modules, if you need more convincing.

Good luck.

 

my tach used to bounce like that. mine got so bad that the car would almost stall. i found out that i had some bad injectors. after i replaced them the car ran fine. might be somthing for youto check.

 

I had a similiar problem with my '89, it was caused by a weak ignition coil.