OK, got a new one for you...

A couple months ago, I wore through the wires that go from the igniter (at least, I think that's what it is) to the distributor by not putting the plug back in the clip by the distributor that it's supposed to go in, allowing the wires to fall down on the power steering pulley and wear through.

When the wires finally wore through, the tach started jumping and the engine cut out...I spliced the wires, and it appeared to be back to normal.

However - now, on hot days, the tach will occasionally read ~500 RPM higher than it should. For example, cruising at 70 it should be about 3k, it'll read 3500 for a while then drop down.

Any ideas? I'm pretty confident in my splicing job, so I don't reckon that's it...but of course it could be.

 

redo your wire..JMO

 

The whole thing, end-to-end?

 

is it a manual trans? last time i saw an rpm off at a speed it shouldn't be was because the clutch was slipping. not to say that's the problem though. I agree redo the wire.

 

It is a manual...not the clutch in this case, as the tach erraticness happens regardless of load/coasting. I'll redo the wire, see if that takes care of it.

Weird that it's temperature dependent. On days less than 100F, it's just fine. Go figure. Maybe the connection breaks down a bit in the heat or something.

 

Weird. Mine jumps around when its cold......

 

Solder and shrink wrap the wires.