....SO I was almost on empty this morning, so I put around 20 gallons in...just shy of being completly filed. I start the truck up and the gauge goes way past the full mark. I put around 20 miles on it so far and it doesnt seem to move. It does cycledown to empty when I turn the key off, but goes right back up to "over" the full mark. Question, Is the sending unit separate from the pump? I don't think I'm going to go thru the hassle of replacing it and dropping the tank...sounds like to much of a Pain in the A**!

 

You first need to put at least a hundred miles on to be sure the gauge has a chance to drop so you can see if there is an issue. 20 miles won't due.
Reason: the pick up sensor resistance is looked at by a digital system in the dash that translates the level for display on the gauge.
Since this is a micro processor action in the dash, it samples the level in long term intervals between samples such that the gauge does not fall in 'direct relation' to the tank level on a 'real time' basis.
Give it some more miles before deciding there is an issue.
A reason why this conversion is done in the dash is because the Computer uses the tank level for some other program control points in testing other systems it needs to know the level for. One is the EVAP system testing.
When the low gas light comes on you generally have nearly 5 gallon left to run on. That should get you about another 40 or more miles until you run dry.
The tank hold about 24+ gallon chucked full on most models.
Good luck.

 

...oddly enough....I put the cluster in test mode and the fuel # is 224, which I beleive puts it at "over full"? Isn't 215 supposed to be the full mark? I guess then with those numbers, its possible that I overfilled it..... I will wait about a hundred miles and see
Thanks
Rich