Horrible mpg in new-to-me Jeep

[tireburner1975]

one thing that I noticed helped bump up the MPG in both my TJ and XJ were new plugs, wires, and cap, if you haven't already done that.

It's a coil on plug 4.0L

But swapping the plugs may help, and the O2 sensors.


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[Fart]

I always got 15-16MPG on my 02 TJ with D44 rear and stock 30x9.5 tires...I'm pretty sure it had 4.10 gears, but I can't remember for sure. Could have been 3.73. Mileage went down a few MPG when I put on a set of steelies with Mud Terrains, but I was still doing better than 11.

Full tuneup is right. And make sure you clean the MAF sensor as part of it. I've seen that pick up 2-3 MPG by itself quite a few times.

 

[braxton357]

My cummins gets 26mpg pulling an 8000lb trailer. Uphill.

 

[rodney eppes]

My cummins gets 26mpg pulling an 8000lb trailer. Uphill.

SHH! don't tell the Oil Co.s; they make you get some off that urine stuff!

 

[Macdaddy4738]

It's a coil on plug 4.0L

But swapping the plugs may help, and the O2 sensors.


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Ah yeah, forgot about that. I only replaced the the cap on the TJ. It was the 4banger one.

 

[Tech11]

I HAVE wondered about the 4 hole fuel injector upgrade/swap. Same amount of fuel just better atomization.

 

[UncleWillie]

Dang the BlueOx gets 11 mpg and she is a 3/4 ton big block.