97 T-100. 3.4, auto, x-cab, bed cover. 19 mpg +- 1. About 70/30 highway and town driving.

Jake, 97's have a 24 gallon tank. Yours probably does and you just didn't realize it. Btdt on some other vehicles. I've put 23 gallons in mine.

That said, Toyota sure was qick to install wrong tanks back in the 80's at least. None of my 86's had the correct sized tank from the factory.

'97 T-100 SR5
'86 Toyota's, the variety pack (all gone)