My tach is nuts

[dacolino]

Hey Ive got a 91 LX 5.0 I just got the car today and the tach (and tach only) jumps around all over the place....driving, idling whatever your doing it just does it. once in a while it will stabilize for a second but then goes nuts again...if anyone knows or has a clue of what to look for help would be appreciated, im totally new to mustangs let alone american cars.
Thanks,
Colin

 

[bgjohnson]

There is a Tach signal wire coming off your distributor. Sounds like the either the pickup is wacky or the wiring has a loose connection.

 

[Mike92GT]

I had a similar problem a while back. Ended up being the tach itself. I replaced it and it's been fine ever since