Any ideas? I've replaced both o2 sensors, all shocks, new tires, plugs, wires, cap ,rotor, tps, cps,map sensor, newish oil change, new air filter, clean spotless throttle body, good tire pressure, new fuel filter. and im getting 13.6 mpg I drive at 60-65on cruse to work every day its not lifted or anything either tiresize is 236 70 16 at

 

Also have new exhaust manifold and muffler, the thing is the gas mileage was damn near the same before I went through and replaced all the stuff that needed replaced

 

Have you reset the ECU/PCU?

 

I cut my pipe off after the cat and noticed an MPG gain.

 

"Good tire pressure" how much is that?

I see you've replaced a lot of parts. Have you done any testing? Does the TPS read right? Why was the CPS replaced? Do you have any vacuum leaks? IAT and CTS report correctly? A compression test? Throwing money at problems only empties your wallet and greys your hair.

Which is of how much relevance to restoring a vehicle to factory condition?

 

I can think of no logical reason for this making any noticeable improvement in fuel mileage but I'd love to hear your method of testing and the actual results. I'm assuming it's pretty loud with no mufflers? That's not even legal here in California, any savings in fuel would be offset by the inconvenience of being pulled over an cited every five minutes.

About the only issue that requires you to throw parts at it is Death Wobble since there's rarely an obvious cause. When it comes to fuel mileage, there are a lot of things that can be checked. Do what Salad suggested. I know a vacuum leak to the MAP will cause a rich condition but so will a lot of other things. Any codes?

 

Good way to die early suck'in those fumes, that's why they the tailpipe goes to the rear bumper. For that reason "ONLY" safety!

 

That little vacuum elbow is fine to the map, tire pressure is at 32. I had to replace the cps because it went out and wouldn't start the jeep. I mean I really just replaced this stuff because it was all factory on a 96 with a 180k. And by resetting the ECU don't you just unplug your battery for a period of time? also no codes are on.

 

IAT and CTS? what are those?

 

Intake Air Temperature sensor an Engine Coolant Temperature sensor (Coolant Temperature Sensor)

In OBD-II XJs the fuel mix is calculated considering:
IAT - Air temp is relative to density and therefore amount of fuel required. This sensor gets dirty since it is exposed to CCV vapors in the intake manifold
ECT - More efficient combustion is achieved at higher temperatures as engine tolerances decrease. More fuel is used when a lower temperature is read.
TPS - Senses throttle position
MAP - Infers flow of air through engine by reading manifold pressure. Vacuum leaks will cause this to report incorrectly and run rich.
CKP - CranKshaft position sensor used for timing
CMP - CaMshaft position sensor used for timing
O2 sensor - Measures exhaust stream for combustion completeness and fuel ratio adjusted accordingly

Probably forgetting something...