i have a 93 w/87k and i put a set of autolite resitors in it and drove from chicago to pennsilvainia and got 300 miles out of one tank and i also changed one o2 befor i left and on the way back i changed the other before i left and i got 28.5mpg on the way back i went 445 miles on the highway and went to 480 in town for a day or two. i had the just the mufflers cut off when i went on the trip, i was also geting 15.5 to 16.5-17 in the city, i did nothing but cut the exhaust back futher and put duel side pipes out the drivers side, ill get pics up soon it looks bad,bad in the good sense of the word. but now ive been geting 12 to 13 in the city all the time, i have stock wires, and filter may need changing but i know it started when i put the sidepipes on, it still has 3 cats and a resonator though, but i think this may be a backpressure issue? does anyone know of any other marks w/side pipes? also i have sct chip tuned by lonnie at blue oval, and still get the same mpg.??????