Tachometer Jumping randomly while driving

[Joey5.0]

So yesterday i was just driving around town when i noticed that my Tach was just bouncing around jumping to all sorts of RPMs randomly. Really weird. Drivability is the same when it does it. Seems to do when i am off the gas but nows it is kind off all the time.

Anyone know the problem? Fuse possibly?

 

[91 HATCH]

i would say that its a short in it.if it was a fuse it would quit working

 

[LtDavis]

bad ground maybe?

 

[Joey5.0]

Where is the ground for the tach?

 

[Deleted member 87397]

Sounds like a bad ground or a short somewhere. I've had it happen before on aftermarket tachs. If it's stock I'm not sure where the ground fror it is, but it shouldn't be too hard to track down if you can get some good diagrams. Just wait for JRichker to post up some fabulous diagram that will help you solve your problems and you'll be set.

 

[Daggar]

Are there any mods to your ignition system?

 

[Nibbie]

I have a simalar problem, the tack gets stuck and the mph bounces all over, I thought it would be the whole gauge cluster

 

[new46stang]

I have a simalar problem, the tack gets stuck and the mph bounces all over, I thought it would be the whole gauge cluster

Sweet...I'm not the only one.

Would love to know how to fix this. I have pulled the cluster out, clean all contacts, cleaned all gounds in engine bay. Next step is to put my fist through it!

Matt

 

[Joey5.0]

I have a Crane Fireball Ps9 Ignition Coil, Ford Racing 9mm Wires, Stock Distributor.

The stock Distributor actually went out today, Fried the cap rotor and condenser, so i am hoping that will fix the problem.