JRZEE2000TR4LTD
Senior Member
When mine runs out, it holds 18.7 gallons. The OP said he put 18.5 gallons in his total, so it's using the whole tanks. If yours is running out before that the pickup is probably screwed up. It definitely shouldn't run out with two gallons left in there if everything is working right.
My 2000 was exactly the same as my 99. Many people on here report almost the same exact kind of results. There's many threads about it. I remember it being one of the first "concerns" I had about the truck.