Alright so i know jeeps arnt known for crazy good mpg, but i think 4 mpg in town is really really bad and isnt normal. when driving to the next town over when i can get up o 55+ i can get 25mpg over and over no matter how many times i test it. but in town its always 4-6 mpg. any ideas about why it would be so awful, im not trying to get it to be 20+ just more then that.

 

How do you drive like a teenager or like a old lady ?

 

Welcome, Spooky.

Two questions first:

1. How are you calculating your MPG?
2. What does the tailpipe look like? Sooty?

 

i try to drive with mpg in mind so i figure closer to grandma then teenager

and i clear the trip when i fill up, when i need fuel i take the miles on the trip and divide it by the gallons i filled up with.
no sooty tailpipe, its just normal clean metal.

 

Ok , have you checked the o2 sensor , and check the trans TV cable it mite be adjusted to much making the trans hold a gear to long .

 

Okay, you are calculating it correctly. I asked that because we have seen quite a few posts from people who think they can judge mileage by miles per fillip, and that isn't even close to being a reliable and accurate method.

Even a poorly running XJ should have you in the low teens for MPG.

So, 4 MPG either means you are burning a TON of fuel (which should give you a very sooty tailpipe and some black exhaust) or you are leaking it somewhere.

I'm voting for a leak.

 

I havent checked o2 sensor, so i guess ill have to look into how to see if its bad/failing.
I assumed engine was getting too much fuel, by stuck open injectors or something. but every other tank of gas i add seafoam and i havent even seen a tiny bit of improvement so unless they r stuck in a way that wont help then idk. also ive looked for leaks and the only leak i have found is from a trans line, but its not even a drip just enough to keep the line wet. and i dont smell fuel from anywhere so im not confident i have a leak.

 

Bad O2 sensor will have you running stupid rich, but you should see a lot of soot in your tailpipe.

 

Well i still dont have a sooty tailpipe, but a search on google to see signs of a bad sensor ive got 4 of the 5 signs so i assume its that. im going to go have orileys check the codes for me. up till now i thought the check engine light was on because of my ABS.

 

Can you post a pic of it?



by the way, a check engine light always means the same thing: PULL THE CODES AND FIND OUT WHAT'S GOING ON.

Too many bad things could be happening for it to be safe to assume you know what it is.

 

i can probably get a pic of it but it will b in abit before i can post, heading to the part store now
cant figure out pictures. but after lookin at it again and alot closer is it sorta blackish, the code was for a neutral park switch so it doesnt even help me out with figuring out my ABS. i think im just going to buy a o2 sensor and throw it in and hope it fixes my MPG if not well atleast its a new sensor.