I've wanted a wrangler for years, actually a cj before that. I sold my Cherokee and made some extra money and waited for my perfect jeep. Newer YJ, 4.0 liter, auto, with a hard top. I looked for a LONG time, and never came across this combination. I then found a 1995 Sahara at a price I couldnt pass up. Its a 4 liter, hard top, but 5 speed. I bought it on sight. Mechanics say its in excellent shape, the valve cover leaks a bit as does the read diff from the filler. I've had the Jeep for a few months now, replaced the cat with a high flow, the last owner put new cap, rotor, wires, ect on on. The O2 sensor is not reading bad, there is no check engine light. The only thing that I can see that is not stock is the 31X10.5 tires on the stock wheels. The rub awful and as soon as it stops raining long enough I'll add some washers to steering stops.
Before I bought the jeep, I asked around and talked to many jeep owners with 2.5 and 4l motors. The conclusion I came up with was that the 2.5l were getting around 23-24 MGP and that the 4l were getting around 19 MPG. I figured I could live with that. But from tank one I have been luck to get 11 MGP and that when I shift as soon as the shift light come on at 2000rpm which I felt was way too low. But when I shift where I feel compfortable I get even lower fuel milage.
My only thought is that its the tires, but I cant believe that some about an half and inch to an inch taller than stock would effect mileage that much.

The tires may be as much as 4" larger, my Wrangler came with about 27" tires, and that may have thrown the odometer and speedo off. Check with a GPS and see.

HTH,
Mark

11MPG sounds just right. All my Jeeps always got anywhere from 9-12mpg. The differance in fuel mileage between a 4cly and a 6cly YJ is about 1mpg.

I think I agree with everything said so far, but you still can and should get better mileage. First, the idea that the 4 will get better mileage is funny. They just go slower.

And you may have a problem with the brakes dragging, etc. As a test, find a big hill. Do it when no one else is around and try to coast down it. See how fast you go. Take another car that gets reasonable mileage and then pull the same test. That one is a real eye opener. Then jack the thing up and spin each tire by hand. See if it requires a lot of effort to spin them.

My two newer TJs get about 14 mpg when I drive with traffic. Thats not good, but its not too terrible. But when I slow down and somehow limit my speed to under 60, it sometimes manages 18 mpg. So I have my choice, be late and risk my neck or pay at the pump.

What kind of air pressure are you running? If you've got it up around 32 or 35# cold, you'll get significantly better mileage (and then go back and do your downhill roll test again!)

27" tires came stock on your jeep? All the ones I have seen were 225/70 15" if I remember right and that equated out to between 29" and 30" I may have the metric numbers wrong but the 29"-30" part I am sure on from measurements with the mounted tires side by side on my Cherokee.

Air pressure? I honestly have never checked. They looked full when I got it.

My 03 Wrangler X came with 215/75 R15, which mathmatically equates to 27.7" dia. Since most tires are optimistic in size, I said about 27". When I put the 31" BFG AT's on, my speedo was off by about 12% based on GPS. 27.5" (approx) + 12% = 30.8", or the approximate size of the BFG's. I was travelling 12% further than my odometer indicated, which caused a false answer when determining fuel mileage by the same 12%. You could be having the same issue, that's why I suggested you grab a GPS and see what your actual speed is compared to indicated speed. Once you know the percentage of error, if any, you can factor that in to get your true mileage.

225/70R15 = 27.4", 225/75R15 = 28.3"
Check here!

Hope this clears things up,
Mark

This message has been edited. Last edited by: Squid in a Jeep,

Try changing the O2 sensor, I went from 11 mpg to 16 in 5 minutes. and the computer said the old one was ok.


"can't be done?"
you don't know jack