Recently I have noticed some strange crap with my XJ. First I started noticing how my street tires are louder than some all-terrain tires on the road, they never were before this month.
Then the mileage. Some friends and I made a trip to greeley to go to junkyards last wednesday. 1/4 tank in 78 miles. I drive 12 miles round trip to work each day. I lose a little less than 1/8 tank in that 12 miles. Keep in mind this is a stock cherokee, and a few months ago I was getting 16 in town, 20 highway.
Help would be much appreciated, putting $20 in my tank every 3 days is getting old.
I have checked, there are no fuel leaks, proper fuel pressure. On wednesday I am getting my tires rebalanced and rotated. I am hoping this helps since the tire noise problem and the mileage problem came up around the same time. But could unbalanced tires really cause that much of a loss?

 

tire noise could be a tire is out of balance or a belt shifted or blown shock
when was the last time you did a tune up?

 

Friday. Changed all ignition parts except the coil, ran some injector cleaner, and I changed the oil about a month ago. I know I don't have a blown shock, that's pretty easy to notice.
I'm thinking one of the balancing weights came off one of the wheels while I was mudding, these problems seem to have come up since I went mudding a few times last month.

 

did you do a fuel filter?

 

I did not but wouldn't a clogged filter cause power loss and lower fuel pressure? the fuel pressure is right at 49PSI.

 

not always... a dirty fuel filter can still have full pressure but still cause bad mileage... I forget how..

how abouta air filter?

 

I blast it out with compressed air every time I open the hood to do anything to it.

 

I would also check you Pcv to see how gunked up it is that could cause bad mileage... and make sure you have no vac leaks 2...

 

I checked a few things tonight, no vacuum leaks and the pcv looks good. The mileage has been getting progressively worse by the day it seems, hopefully I don't burn my whole half a tank going down to the shop on wednesday.

 

o2 sensors? Map sensor?

have you tested them?

 

You're not doing yourself any favors by doing that, just ruining the filter and contaminating the "clean" side of the filter.

Is the check engine light on? Or does it even function?

 

yep, check for codes, if there are any....

might be tps out of whack a bit.

timing is right ya?

just some more things to check.......


good luck sir

cpnwrench

 

x2. bet its 02

 

Sounds like maybe your tire noise isn't a tire noise. It could be a hub bearing. If you noticed this after mudding and its getting worse. Id say you have a bearing failing.

 

X2....that was my first though,if the bearing is draggingit's really gonna affect your milage,and sooner or later it is gonna cause some bad damage,jack the front end off the ground and see if you have any play on the wheels and give them a spin to try and isolate the noise.