What is the gas tank capacity on the 1st Gens?
I have found both 13.5 and 16.0 gallons listed. Was the 16.0 for a long bed?
Just trying to find out. Been driving the '81 around a bit now but am finding that the gas gauge is not very accurate, suspect the float sensor is sticking..

 

I've been told 17 gallons.

 

13.5 is short bed, 16 is longbed..found that in my 1979 Toyota Pickup's owners manual under capacities

 

Before you go thinking its the float sensor take a look on the top of the tank on the sending unit where the wire goes into it and see if all that plastic crap is broken off or not. On my 82 I have no gas gauge as that plastic stuff has broken loose and the wire is shorting out on the steel. Sometimes it would work correctly and sometimes not and I found that it changed as I wiggled the connection. If thats the problem take the sending unit out and put a new wire on it where it comes through the top and put some JB weld on there to make sure the wire can't move anymore. The plastic stuff lasted 26 years so the JB weld should be good for a while.

 

Cool. Sounds like mine is 13.5 since the trekker is a short bed. I checked my FSM but it did not have specs for capacities that I could find and no owner's manual
As far as the sender unit, I will check it out this weekend. Overall the truck is in pretty good shape but am finding a few things here and there but oh well-I almost like driving the '81 better than the '05 tacoma