88 XJ 4.0 getting 6 MPG

[Traimech]

Hey guys,

First off, pleasure to met you guys. Im new here.

Secondly, I need help. I picked up this 88 Cherokee, great condition, and runs nicely. Shes running the 4.0L V6, with an aftermarket magnaflow exhaust system and a lifetime reusable air filter.

Heres the catch: Im only getting 6MPG. (In Canada, it works out to be about 200km to my $80 tank of gas.) I just replaced the O2 sensor and got little-to-no difference in the fuel usage. Any ideas for my next course of action?

 

[cruiser54]

Start with fresh tuneup hardwar including plugs, wires, cap, and rotor. Inspect the vacuum harness for leaks, cracks, melting.

It's gotta run like crap if it's pushing that much fuel through it.

Any other symptoms?

 

[Ian Christiansen]

Hey guys,

Shes running the 4.0L V6

If it's morphed into a V6, that might be a problem.

 

[srmitchell]

LOL^.

You've got a straight 6 man.

 

[styx]

The last time I bought an older XJ it had bad o-rings around the injectors and was leaking fuel...that was not good for mileage. I'd check for leaks if it's running decent.

I blame all gramatical errors on Apple and the iPhone.

 

[Traimech]

LOL^.

You've got a straight 6 man.

Thanks for the correction. haha.

As for symptoms I havent experienced anything majorly problematic, the Crank sensor did fail a week ago. I replaced it immediatly and she was back running. Ill look for leaks in the vacuum once the weather brightens up a bit, since I dont have shelter to work under.

 

[badron]

What tires gears are you running? What other mods if any including bumper winch roof rack etc. Is it a Slush-O-Matic? Do you let her warm up a lot? that will eat gas. It's an 88. That's a tired old motor you got there. you may never see much better.
I like the good tune up thing. fill tires to proper PSI. Pitch all the crap in the back and good luck

 

[turbojeeper]

I had a 90 with the renix system in it. It only got 9 mpg. It didnteven change when I lifted it and put 32's on it. Ran great with no leaks anywhere