i would ditch ur cat if u can, (ie local laws). i did that and found my little 2.3 got way better mpgs, plus a ton of horsepower . Google ford ranger 2.3 performance. there is a guy that tried all the home tricks(throttle body spacer, blocking off EGR, and taking out the baffles in the intake, ect) and then went out and checked his mpgs. It is a very helpfull article, i belive he was cranking out high twenties or more.