Yes ac has a big effect on the mileage paired with your heavy foot it's possible to get down that low, I get 19 when playing a decent amout, ac and completely good driving with mine gets also about 19 so turn off ac or calm it down some, that's way to much heavy footing, ur car has a 15+ gallon tank but doesn't hold more than 13.5 because of vapor space
BV heads, P&P lower, windstar upper, comp 218/226, 4.2 bottom end, 3k stall, flow 40's, O/R x-pipe, Pacesetter lt's, Xcal2, 65mm tb, CAI, 8.8 w/ 3.73's, MM LCA's
coming soon: blower cam and intercooled M112
dealer for Ortiz Performance; tunes, cams, etc. PM me!