Re: gas mileage? 4.0 what can i do?
By the way, this won't work for 4.0 cars, but 4.7's from 1999 to 2001 can have the trans reflashed by the dealer to upgrade to a 5 speed vs 4 speed overdrive. Cost me $100 and worth every penny. Lowers RPM by about 400 added another MPG on the highway.
Lowering restrictions to intake and exhaust should mean less throttle required and therfore better MPG for 4.0's but I'll reserve judgement till I can experiment a little on my newly aquired 2002 GCL.