I have a 1995 Grand Cherokee with the V8, and np249 t-case. The speedometer jumps around sometimes, the tachometer reads low, and the odometer sometimes stops working. I think the problem is in the cluster itself, since the tripmeter and gas mileage display still work correctly on the overhead display.

The tachometer reads about 1750 RPM at 65 mph, and reads 0 rpm at idle. it seems to be pretty consistent, just low.

Any ideas? Is there a big scary-looking connector behind the cluster that is just loose?

 

1750 RPM at 65 MPH sounds about right to me. What size tires are you running?

 

I'm running 235/75R15 tires. Slightly wider (And a whole lot easier to find) than the 225/75R15 that is stock.

1750 rpm may be right for 65, but 0 rpm is certainly not right for idle. Sounds like it's going about 600 rpm at idle when it is warmed up.

Speedometer is still off by random amounts at different times. Today it was off by 20 mph or so - I was going 65 by my GPS, at an indicated 38 MPH. Leaving work this morning, the speedometer was correct - but the tach was reading 1500 RPM. By the time I got home, I was reading 1750 rpm again.