The guage on my 1981 pickup is staying on full. I drove around to see if will go down and still stayed on f. Then tried to refill the tank to no avail.
I removed the sending unit and played with it manually and it seemed to work fine. So i was thinking it was just stuck. When i installed the sending unit and gas tank i still had the same problem.

 

most likely the guage in the dash cluster .. mine was
do you have a manual ? check it , for the proceedure



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