Amp gauge keeps going left to right ?

Try the headlights (at night) and see if they get brighter,  get a volt meter, and see if it jumps up.

If it goes up to 17 Volts, you might have a bad voltage regulator.

Good Luck

Check ALL ground connections. Most importantly the one up under the dash on the other side of the ground terminal for the battery.

Check for loose or burnt connections on the back of the ammeter.  

John

Grounds are the root of all evil....

The amp gauge in a Pantera is known for jumping around. You should check all of your grounds, but what many of us have done is to put a jumper wire across the amp gauge connections. That acts as a shunt and will help to keep the gauge from bouncing around so much. All of the power coming to and from the battery goes through that gauge and it isn't a good design and at best is not very accurate when it comes to telling you the actual amp draw on the system. That is one of the reasons why you will see a Pantera that has a volt meter gauge in place of the amp meter.

All of the factory Veglia ammeters that were installed in the Pantera had a design fault, it is only a matter of time until they fail. Failure can be odd operation to severe over-heating and permanent damage to the ammeter and cables.

Pantera Electronics rebuilds and restores the Veglia ammeter by replacing components and machining to resolve the issues.

Ground quality connections are not related to the problem.

Rewiring does not solve the problem, it just reroutes current and renders the ammeter useless.

I recently added the shunt to my factory ampmeter and also plumbed a new 8 AWG cable directly from the battery to provide power for the headlight and radiator fan circuits via relays and off load lots of current from the ignition switch. I used the tutorials on panteraplace - they are excellent http://www.panteraplace.com/Page9.htm  The electrics behave alot better now.

On the first day after I bought my car, my Amp meter was jumping like crazy - full scale on both sides.  It worried the heck out of me.

I was traveling - driving the car from Gardnerville, Nevada to Tucson, Arizona.

I solved that immediate problem by ensuring I had good connections at the battery, and at the ground between the battery and the chassis.

Check the simple stuff first, then go behind the dash on the Ampmeter connections.

Good grounds are critical on these cars, as everyone on this board will tell you.

Rocky