I have a 94 S-10 2.2L and I am almost positive it holds 18 US GAL
35 gallons for a long bed and 18 gallons for a shortbed.
Since I couldn't find an answer here I was able to get one at the local parts store. 13 gallons.
About 15 gallons
16 gallons
26 Gallons (From the Chevrolet website)
19.5 Gallons
17.2
16.1 Gallons 16.1 Gallons
23 gallons
15 7/8 gallons
24
26 Gallons