My Jeep is drinking gas and it's only getting 11 MPG and has been as low as 8 MPG. I am going to tune it up, remove the air restrictor in the throttle body tubing. I'm going to remove to Cat. Convertor and maybe go with a smaller tire size. I'm currently running 31-10-50's. Maybe go with a performance chip also. Has anyone tried any of this and how did it improve their MPG and what does everyone else get? I have a buddy that swears he gets 18 around town and 20+ on a trip if he drives decent speeds. I mean how could you not run decent speeds, my jeep barely has enough power to pull out of it's tracks and it's a 5 speed. I can't imagine how weak it would be if it was an automatic. It's my daily driver now so I need to get th emost bang for my buck.

mine got avg of 15 if i didnt wheel at all and putted around i got as high as 17

Mine gets 12.5 MPG

Is there a way to tell how much your odometer is off when upgrading tire size? Because I think it would change your mpg with it being off.

I was getting about 11 mpg average city and highway. I actually went to the 31s from the original 30" tires and it didn't make a difference. Recently I replaced the ngk plugs with autolife and am now getting around 13.5. It's a little better but not much. I consider that the price I pay for driving a Jeep (which isn't much considering how much I love to drive it) As for all of the mods you are planning to try and help, I would seriously advise you to check some of the older threads concerning mileage. You will find that a lot of these things are just going to be a waste of money. It is what it is.

since it is a 94 then there stands a chance ur cat is clogged up, and that will kill ur millage and performance. my van is a 98, and ive had to replace the cat on it cause it was clogged up, those things aint cheap btw. just switching the clogged cat out got me like 3 mpg. u could get more, my engine is running insanely rough, beyond just a tune up. lets hope it dies this weekend in a rather dramatic and epic way.

I think I figured it out. From a stock 215/75r15 tire that spins 748 rpm to a 31x10.5r15 tire that spins 677 rpm. A difference of 71 rpm. Which would mean in about 10.5 miles the tires spins 748 rpm less. So it would make your odometer off 1 mile every 10.5 miles driven. Would be slighty different depending on stock tire size. So you would add miles to your odometer to figure actually mpg. 1 for every 10.5 miles driven.

As I mentioned earlier mine has no Cat so it can't be clogged.

Mine gets about 8-10 on the highway, and in the city, well lets just say I've got fuel bongs lined up behind the back seat.

When I got my YJ, it got around 10 MPG. It has 180K miles on it. I did a compression test and the rings were great. It ran a bit rough so I Seafoamed it. In the tank, in the oil, and dumped in the throttle body. Then I gave it new cap, rotor, and Champion plugs(these engines are old school, so use old school plugs). A new air filter, and removed the restrictor. The big one was a new timing set and cam and lifters. It runs smooth as glass and I get around 14 in the city. On the highway, if I stay below 60 MPH, I get around 18mpg. Best of all, no stinky exhaust and it doesn't sound like a diesel when at idle. I also have a 5 speed with 31x10.5 tires. Do the compression test, if it is in spec, get to work and save some gas. If it is weak, throw a SB chevy in it better mpg and more POWER! I put about $450 bux in my little project.

94 4.0 5 Speed, soft top, no air. Mostly stock, 30x0.5BFG ATs, 112,000 miles, owned since new, and I checked today when I filled it up, and I got 16.75 MPG on the last tank(I know this isn' entirely accurate, but it's all I have, and I check almost every time I fill up.) These miles were mostly around town.

4WD, anything over 65MPH, and lots of short trips all definitely reduce my mileage, but I don't think I've ever gotten less than 14-15. On longer trips with HWY miles and keeping it around 55-60, I can get better than 20MPG. The EPA sticker claims 15-19, so I figure it's still right in there.

The gas guage is almost worthless. It will stay on full for the first 100 miles, and plummet to 1/4-3/8 on the next 100, the last quarter slows down again. It's always been that way, and when it states I am in the red (Less than 1/8) I still usually have more than 4 gallons.

I'd replace all the fluids (You should do that anyway, if it's been a while), the filters, wires, plugs, etc. Check for fuel leaks all along the line, but especially near the pump. Clean the injectors, even if it's just additive, and see if any of that helps. Even if it doesn't, it's good for your rig, so there's no loss. Also, a simple thing is to ensure you have good pressure in your tires. I noticed that after wheeling, when I have 12-15 PSI, I get crap mileage. I like to run about 32 PSI all around for street driving. The factory sticker gives 28 front and 32 rear, but that was on the 215 GY Wrangler POS tires it came with.

That's all I can think of to check right now. Good luck.

I have a 93 wrangler which had a low oil pressure reading however the engine runs smooth along with good idling...I decided to replace the oil pressure switch which corrected the low reading problem , but after driving 300 miles the oil reading went way to the right past 80....i believe I have a broken guage and would like to replace it...howevere not able to find one...can someone help..or would you agree that it is a broken guage...thanks Doug

99 Wrangler, 2.5L 4 cyl. Been trackign mileage on each fillup (iPhone app). I get about 17.5 average city/highway. Have gotten 22 between fillups (don't know what I did for that).

I consistantly get around 20 mpg!!! Even with my mods, just drive smart

Well.........Hmmmm

don't get discouraged!! try tuning it up a little
Like SilverLion said these 2.5's love the plaino champion plugs.
They are like $1.25 each
I would start there it made a big difference with mine. previously had Bausch platinums.
make sure your air filter is clean etc.
start cheap and easy see if it helps

Getting 16.67 MPG -- just checked it.

i have gotten anywhere from 17-22 mpg in the city havent done much highway driving.

Oh yeah forgot.. i get about 12-14 mpg mods in sig.

Something is wrong...
My 2.5 is getting 17-19mpg.

Well it's pretty obvious that there is something causing mine to drink the fuel.

This is the old iron duke GM used for years keep your tune-ups simple. I installed splitfire plugs in mine and the mileage went up 25 miles per tank, 31" swampers on it.

HEARING ALL THIS IS REALLY GETTIN ME MADD.... i just bought a 1990 wrangler with a 3 inch ;lift and 31" tires ... hows my gas gonna be... gotta wait and see

Well good luck brother, you might as well get mad because the mileage sucks.

I have a 89 TBI 4 cylinder(not currently spit'n fuel) and a 93 EFI 6 cylinder and the 6 gets 18 to 20, while the 4 is down at 12 to 14. I think it's because I tend to keep my foot in the 4 more. They both have Split Fire plugs.

That's almost impossible lol, are we talking mostly freeway under 55 mph or what?

Yeah I would also have a very hard time believing that.

my 94 4.0 gets 17 mpg.

'89 4.2L getting 15.6 I just checked tonight

It is possable cause thats what i get... I shift at 2200 RPM's and dont floor it to get to the next gear. I take my time and stay 55 and under!!!! And I drive mostly on country rounds and city