My 2003 Bonneville SE Holds 18.5 Gallons.
I think a 1992 through 2005 Bonnevilles hold about 19 to 20 gallons of fuel. To double check this answer check the owners manual and see if it saids anything on fuel compacity
21 gallons
16 gallons
12.7 gallons
20.9 US Gallons.
18 gallons found at http://www.new-cars.com/2003/pontiac/pontiac-aztek-specs.html
14 gallons
16
13.25 dry.
About 12 gallons in my 2003 ==According to Haynes,== 15.2 gallons. FriPilot
16.5 gallons.