My '86 2.8 has a little problem with the RPM Guage. The RPM guage operates smoothly expect for when I put an electrial demand on vehicle. For example while driving on the free way, lets say my RPM is reading a constant 2500 RPMS, I put on my turning signal the RPM gauge will jump up and down with each flash. The amount of jump is increase if I have my headlights on, brake lights and so on. . . The more electrical applainces I have on the larger jump. I think it maybe a bad ground. Any suggestions?
Mike

Sounds Like A Weak Ground. Make Sure You Have A Good Ground Strap From Engine To Frame. I Have Two Ground Straps On My Engine To Frame. You Cant Get Too Many Ground Straps.

A weak alternator and battery will also cause the same thing as this. Mine did this same thing even though the alt. light never came on, it was still only putting out very little current.

About ground straps: Is there supposed to be a braided wire coming from the engine near the waterpump? It has a connector at the end of it shaped like a jagged washer that is not connected to anything. I noticed this the other day. It's just bolted to the engine block somewhere.

that one usually goes to the bracket for the deck lid.