This one is driving me nuts. A while back, fuel gauge started going extreme erratic. At startup it would shoot over past FULL (literally pegged horizontal), then, a few miles down the road drifts dead left past EMPTY. Then occasionally meanders up to actual reading, then fluctuates between all of them. So, replaced sending unit with new. Fixed all the weirdness described in the first two sentences but would still occasionally shoot up past full at startup but would come back to normal after some driving except...a new squirrel popped up: now the gauge won't show correct level once I get below half/quarter tank. Currently, as I write, I know that I have about 1-2 gallons in the tank based off of trip meter math. But gauge says I have 1/2 tank.

Amongst all of this, I replaced the AS module (unfortunately, used) and that did nothing to correct this issue.

Clearly, the new sending unit fixed the original problem. Could the new (used) AS module be just as bad as my old one?

Any thoughts from the gurus out there? What should I do next? I typically like to try to fix this stuff myself before I have to resort to my Jag shop guy, but don't know what I don't know.

Thanks for any insight.

*******UPDATE***** POSSIBLY FIXED************

After all of the above and after a lot of searching online and on this forum, decided to do the one thing I had not tried: fidget with connections behind the gas gauge. I stuck my hand up there and simply rubbed along the nodules (they are covered in a rubber-like substance) and lo and behold I watched the gauge drop to what is probably an accurate reading, just above the red line. I am unaware of what I actually touched. No exposed wires. Like I said, there were smooth rubber coated nodules behind the gauge and I simply rubbed them. The gauge corrected at that point. So, take it for what it is: a wild *** attempt at something.

So, I will now go fill 'er up and see if it's still tracking, then see how it does with a cold start in the morning. That is typically when it shoots over past F before correcting.

If anyone has some insight as to what I actually did behind the gauge just by rubbing the nodules, please advise. Also, the gauge is showing the same reading whether I use my previous original A/S module or the new-used one I just got, so I'll keep the original in the car for now and if it ever does eventually go bad, I'll have the spare.

 

I’ll explain what you did. Anytime you rub the nodules, things get happy. Essentially you removed any built up resistance. Electronics are tricky. Dont go on rubbing people’s nodules though…