HELP POOR GAS MILEAGE!!!!!!!

attaboybill · 09-04-2001, 12:19 AM

I have a 98 TJ 4 banger with 50K miles on it and 31" BFG tires. For about the past year I've been getting horrible gas mileage (~200 miles per 15 gallon tank). I had to replace the exhaust manifold gasket (cuz it was leaking) and that helped my mileage some......but it still gets really bad mileage. Jeep consistantly tells me that it's the bigger tires and the Altitude (Live in Denver). I don't believe that they're telling me the truth. PLEASE help me!!!! Should I replace the O2 sensor??? A local mechanic recommended that.....but 120 bucks better produce some results!

flsar · 09-04-2001, 02:16 PM

Jeep is most deinfitely correct. I had a 2000 2.5L with 33" tires a got around 233 on a full tank. the only other mod i had was a throttle body spacer.

JPMan-TJ · 09-05-2001, 01:58 PM

Something is a miss - I have the I6 and with 32" tires. I get anywhere from 250-275 per tank. The O2 sensor may or may not help. But something isn't right. I do believe that the fact you live in Denver may be the cause of some of it but not that much. I would keep after DC and the local Jeep dealership about it.

wdstj · 09-08-2001, 09:51 AM

My 98TJ, with 58,000 miles, had the poor gas mileage. It turned out that the problem was dirty fuel injectors. Run a bottle of injector cleaner through a couple of tanks of gas, and see if that helps. Also clean the throttle body, if you have not already.

I am now back up to my normal 230-250 miles per tank, with the 4.0L and 5-speed.

09-04-2001, 02:16 PM	#2
flsar Registered User Join Date: Jul 2001 Posts: 27 Profile Gallery Classifieds My Jeeps	Jeep is most deinfitely correct. I had a 2000 2.5L with 33" tires a got around 233 on a full tank. the only other mod i had was a throttle body spacer. __________________ 2001 Sport, 4.0 bored over .030, perfomance cam/chip, 4"pro comp stage 2, gibson cat back, 33" pro comp AT, and lots more little goodies

09-05-2001, 01:58 PM	#3
JPMan-TJ Registered User Join Date: Feb 2001 Posts: 532 Profile Gallery Classifieds My Jeeps	Something is a miss - I have the I6 and with 32" tires. I get anywhere from 250-275 per tank. The O2 sensor may or may not help. But something isn't right. I do believe that the fact you live in Denver may be the cause of some of it but not that much. I would keep after DC and the local Jeep dealership about it. __________________ [b]JPMan-TJ[/b]

09-08-2001, 09:51 AM	#4
wdstj Registered User Join Date: Sep 2001 Location: La Quinta, CA Posts: 16 Profile Gallery Classifieds My Jeeps	My 98TJ, with 58,000 miles, had the poor gas mileage. It turned out that the problem was dirty fuel injectors. Run a bottle of injector cleaner through a couple of tanks of gas, and see if that helps. Also clean the throttle body, if you have not already. I am now back up to my normal 230-250 miles per tank, with the 4.0L and 5-speed.