Hi I have a question maybe you guys can help me out. I have a 1984 Subaru gl with 4 speed. When I start the car the rpm needle will jump up to like 2 or 3 and makes a weird sound then comes back to 1. This happening with it out of gear and sitting still. Now when I take off I’ve noticed it will still do it on acceleration and the car will loose power for that second that it’s happening. But once I drive the car for say 20 minutes it stops doing it. I had to jump the car off today and can hear a distinctive whining noise coming from the engine when this happens. Anyone have any clue what this might be? Thanks   

got another tacho you can hook up to the coil to see if it does the same?

I know of a high energy coil set up on a totally different engine had a jumpy tacho - new seat of HT leads fixed it.

Diodes in alternators are reported to be source of some whining noises, try belt off alternator for a moment when you know you can make noise

I tightened the alternator belt and it still does it. It’s like the clutch is slipping but it also does it out of gear and at idle 

Probably worn distributor bushings.Pretty common.

See if you can wiggle the shaft.Any more than barely perceptible movement is too much.

Another tach won`t read right either as the ignition primary signal is messed up.

dealt with this recently. ON mine the wires to the coil were loose

 

Have to rebush the distributor shaft. Or replace the distributor. Look up Philbin Manufacturing in Portland, OR. They can rebuild it. 

GD