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General Forums => The Mess Hall => Topic started by: T.H's TJ on January 23, 2006, 09:32:02 PM

Title: Dropping gas milage
Post by: T.H's TJ on January 23, 2006, 09:32:02 PM

I have 99 TJ. When I got it I would get 18 MPG with the air running, sitting on 235 tires. I put 31's on and i still got 17 or so. After that it just kept going down the tube. I know my speedo is off by 9%, but i figure that in. Now am lucky to get 15, and i drive like a grandpa shifting at 1700 to 1900 rpms, but nothing seems to help. Any sugestions?

Title: Dropping gas milage
Post by: Jeffy on January 23, 2006, 09:52:04 PM

What is the mileage?  Any fault codes stored in the PCM?

Title: Dropping gas milage
Post by: T.H's TJ on January 23, 2006, 10:01:01 PM

I don't know about stored codes, My old jeep you could turn the key back and forth to get them, but can't on this one and i don't have a code reader. never seen the check eingine light come on. My jeep has 82000 on it.

Title: Dropping gas milage
Post by: Jeffy on January 23, 2006, 10:13:20 PM

With that many miles, it could be an O2.  I'm not sure if it would be an upstream or down stream though.  I've heard that when one goes, your mileage might start dropping.