My '83 GL Wagon was running great then recently it's started having a jumpy rpm needle. The needle jumps from normal rpms to almost redlining the needle either stays high or drops back down and still jumps just at lower rpms. She is shifts gears fine, so I'm at a loss as to whats wrong. Suggestions?

The shaft bushings in your distributor have too much play. Either replace them, replace the distributor, or have it rebuilt.

 

GD

Is this the same for a gl-10s digi dash?

Unlikely unless the GL-10 is a carb or very early turbo ('85/'86). It's probably grounding issues with the digi-dash. The bushing wear on the earlier designs causes issues with the reluctor gap and makes the coil fire more rapidly even though the engine is not spinning that fast - this makes the tach signal (which is just the ground signal from the negative side of the coil) more rapid and thus the faster tach reading. When they get real bad it will read many thousands of RPM faster than the engine is spinning and will cause preigntion issues and may even make it undriveable.

 

GD