Help with tuning options

[The Fugitive]

I have been researching to see how/if I can advance the timing a little and possibly lean the mixture at highway cruise settings, if its safe to do so.

I have a 2000 Wrangler with a fresh, stock 4.0. It runs fine, no check engine light etc. I am not looking for more WOT power, I'm looking for more efficiency on the freeway. Currently 14 mpg.

My thought process was to install a wideband air/fuel gauge and if its a bit rich at freeway cruise perhaps could slightly lean. And add a couple degrees of timing. The changes only need to be in the freeway cruise range (2000-3200 rpm and 15-20 inches manifold pressure) and not the entire fueling/timing map.

I've been reading about the JTEC pcm and getting conflicting information as to whether it can be tuned or not. I've also been reading about the Megasquirt, Unichip, Split Second. I am also unsure if a piggyback style tuner adjusts MAP voltage to change fuel ration, if the PCM with disregard it during closed loop conditions.

If anyone can point me in the right direction, I am all ears. I hope you don't mind a non-stroker question, but you guys seem to do a great job modifying and tuning a slew of engines.

[FlyinRyan]

I custom tune, and specialize in JTEC.

[shawnxj]

ryan will fix you up. just use your stock 2000 pcm