Installed my Autometer Phantom II Gauges a little while ago and for a few miles they all worked fine but soon the pyro started acting up, the needle fluttering all over the place. It got worse until now, when the only time it seems to show an accurate reading is while coasting and sometimes when cold starting(no throttle input). If I touch the go pedal even slightly it freaks out again. I have checked all connections. Do I need a new gauge?

 

check the probe where the stainless tube and braiding meet I had one with wire failure at that pont. With ignition on have someone watch gauge and then wiggle the braided part and see if the needle on gauge bounces.

 

I've heard this about Autometer gauges and a lot of people say that the electrical grounds from the gauge should go directly to the battery. However, I don't know if it's an issue of the needles fluctuating or if it just reads wrong, high or low. I have an UltraLite II pyro in my 1st gen and it's grounded to the body but doesn't fluctuate at all and I can only assume it's reading correct .