Horrible Mileage in a '97 TJ

[duffy]

Hoping someone can give me a little assistance.  I've got a '97 TJ (4 cyl version).  It is lifted, with 33" all terrains.  However, I get terrible gas mileage.

I've replaced plugs, wires, etc., but for me to drive from Shawnessey to downtown is about $15 in gas.  If I'm lucky, I can get 200 km on a full tank of gas.  Is this normal, or should I be getting a little better than that?

One thing is my intake/exhaust manifold does leak a little - one of the bolts snapped off, and I haven't managed to get it fixed yet.  Could this be part of the cause?  (on a side note - anyone here any good at fixing something like that

Thanks all, any assistance would be appreciated.

[cablesmurf]

It's a Jeep thing, you wouldn't understand.

Seriouly though...they suck on gas milage. Yours may be more severe though. There are many things that can cause this problem, I could be here all night going thru the list. I'm sure one of the rollerskate guys will chime in soon though.

Good luck.

[big black dodge]

is she running right?

[duffy]

seems to be - really lags out when starting, but other than that okay.

I do expect to get horrible gas mileage, however it seems a little bad - if we go out to McLean, I have to fill up in Shawnessey, then fill up again in Bragg Creek - if not, I can't drive to Maclean without a jerry can of gas.

I think the best expression I heard was "it's like driving a lunchbox down the highway", and I'm not complaining - just hoping there's a way to improve it

[buckshot]

I would check o2 sensor have seen them go and not come up on dash could explain being a little slugish off start as well  will make terrible milage makes it run like it is cold all the time over fuels
just suggestion

[RedApe]

This is definetly a "welcome to the club".

I have found a cure for this poor gas mileage, and we are now getting almost 800 Km's to a tank.

The fix cost us $3000:

[sgo70]

HEY! it says no parking!!!

[cdnhonda]

ya i would say check o2 sensor how much of the bolt is sticking out of the head if any or check you cat. it might be shot as well

[cdnhonda]

ya i would say check o2 sensor how much of the bolt is sticking out of the head if any or check you cat. it might be shot as well

[Jaguar]

I think I'm the ONLY one happy with the gas mileage... 520KM on 1 tank! WOO HOO!! Did you re-gear when you jumped up in tire size?

[duffy]

The bolt broke off right at the head, so I think I'm going to have to pull the head right off to get it drilled out.

Haven't changed the gears, still running the stock ones.

[Jaguar]

Re-gearing definately isn't cheap, but it will help restore your gas mileage and power.

[iceman]

About your manafold don,t bother getting it fixed the reason your bolt snaped is because your manifold is warped it will snap off the the bolt at the other end soon it did it twice to me the best bet is to replace it with a header this will help with you fuel milage (not a lot but abit ) it will give you a bit more hp i had an auto w/2.5 + 32in on gamblers  you could also replace your factory air with a kand n air filter also replace both your o2,s one last thing on my 97 tj i had the computer up dated at tower they say its like going from windows 95 to windows 98 this worked for me p/s i also had to replace the cat it was cloged  good luck

[Abrasive]

A few months after the lift/33's went on my 4.0L, my range dropped from around 430km/tank to 200-240km/tank. I had a local mufler shop in Red Deer put a new muffler in, replace the rear O2 with a simulator and put a test pipe in place of the cat. That seemed to help, but only a little.
Next, I did my plugs, wires, car and rotor (Managing to dain the battery in the process). Once that was done, I fired it up and she was idling at around 2000RPM. Once the battery had a chance to recharge, I did a soft reboot (took the negative terminal off the battery post and left it sit for an hour or so to allow the caps to discharge) and it's been fine ever since. Back up to around 440km/tank and have more power on the highway.
If you haven't already tried it, do the battery thing to reset your system. If that does't work, my next step was going to be the front O2 sensor, then moving on to the fuel system if that didn't work.

Good luck,
Kris

P.S. To give you a point of reference, my jeep is a 6cyl, on 33" tires, with 3.55 gears.

[Dragonmaster]

I know when my e-manifold cracked on my 4 cyl with 31's I went from 400km/tank down to 300.  On top of that the leak caused to o2 sensor to read incorrectly and dump fuel into my system which clogged the already ailing cat and then the o2 sensor failed.  Replaced te header, o2 sensor and cat and went up to 450km/tank.