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Old 05-29-2012, 10:41 PM
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Join Date: May 2012
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Poor Gas Mileage and Performance

I have a 2004 Jeep Wrangler X 4.0 with 42,000 miles. I am getting 7 miles to the gallon and cannot exceed over 60 mph on the hwy. I have replaced the following in the last year: new oil pump, oil pump gauge sensor, new spark plugs, new catalytic converters front and along the exhaust pipe, new throttle position sensor, new O2 sensors (all 4), new thermostat, new pcp elbows, and new air filter. It all started with oil gauge peg to L. My buddy thought it was the oil pump and put on a new one. No change. I then put on a new oil pump gauge sensor. That took care of that. Then I continued to hear a rattle coming from the driver side in the engine compartment. I then changed the spark plugs, air filter, front driver side wheel bearings, brakes, pcp elbows, and thermostat. Still had a rattle. Took it to a muffler shop, replaced the catalytic converter on the exhaust pipe and he cut open the converter in the engine compartment. He took out the broken pieces. That worked. I Then got a cylinder 4 misfire. Replaced the spark plug. I then drove 900 miles with no CEL however only got 14 mph with A/C off. The next day CEL P0432 Catalyst behold threshold Bank 2 came on took it in to muffler shop and changed out the catalytic converter under the hood and all 4 O2 sensors. No CEL and still no power and poor fuel. I took it to the dealer today and had the distrubtor checked and was off 21 degrees. Left dealer with more power until I tried to climb above 60 MPH and could not. I got 7 mpGallon. I am schedule to take it back in tommorrow. Can someone Help me figure this out. Thank You.
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Old 05-30-2012, 07:24 AM   #2
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Location: NE Ohio
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WOW at a loss for what it could be... I can understand 14mpg is typical or not really and issue since its "A brick on wheels", but only getting 7mpg WOW.

Is this a 4banger or 6cylinder.....

This might seems stupid but..... is it in 4wd or 2wd.... sometimes the linkage can bind and lever will look like it's in 2wd but never shifted out of 4wd. The linkage on mine binds up once and a while, until ai replaced will new linkage.

98TJ / Hi-Lined / Zip Lockers / 35s

Family Rig / Tow Rig: 08 Tundra & 16ft Trailer
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Old 05-30-2012, 07:09 PM
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Thanks for the response. It's a 6 cylinder with 33" tires and 3" lift. I did have the timing readjusted. Seems to be running much better. Now getting around 10 in town. Still not much power when driving 55 into the wind. While driving with the wind behind me goes no more than 65 without flooring it and raising rpms between 3000 and 4000. I haven't checked the linkage. I understand these don't do well on gas, however, I should have so much more highway and towing power. From 0 to 50 it runs awesome. I will check the linkage and repost. Thank you.
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Old 05-30-2012, 08:48 PM   #4
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Location: Joshua, TX (DFW area)
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I just got an 03 a couple a months ago. Minus the rattling, had the same poor milage problem. I have 33's on mine, unfortunately I have the stock dif gears (3,07) as long as I don't use fifth gear I get a constant 15-17mpg on the highway. Of course my speedo is not even right. It reads 60, really doing 68-70. I run about 2200 rpms at 70mph ( 60ish on speedo). Also I shift at 2800-3000rpm through all the gears to compensate for loss of power due to tire size
Just wanna go jeepin!!
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