Try unplugging the sender and have someone watch the gauge as you ground the wire. From ground to open, the gauge should make the full sweep. This will prove the gauge and you will know its the sender. Rick
Logged
69 Swinger,3.54 Dana, 400/499, Stealth heads, Crower 262/266d, .686/.696L roller,11 to 1, 950 Bigs, E85 carb. Best so far, 10.82 @ 124mph through the mufflers.