ScottH

Ok so today I filled up and I was pretty astound at the MPG I got out of my last tank of gas.

I have a 00 Cherokee Sport, 4L Auto. Mods are in my sig (otherwise stock).

Here is a log of my last few fill ups:
_________________________
June 29th, 2011
- 16.97MPG
- 142,637 Miles (dist:286)
Notes: 85-90% of this tank was used on the highway.
_________________________
July 5th, 2011
- 14.25MPG
- 142,872 Miles (dist:235)
_________________________
July 20th, 2011
- 10.93MPG
- 143,057 Miles (dist:185)
_________________________

Most of my driving is local city driving. But even when I was getting between 13-15mpg I was doing the same city driving. I am pretty conservative when it comes to driving (light right foot).

There is no engine lights on. Nothing is out of the normal (idle etc). Just not sure why I'd gotten such a crappy MPG out of my last tank.

Diesel

Sounds like shot O2 sensor, odd its not throwing a code. Fuel leak would be my next guess

ScottH

I think I will swing by my buddies shop tomorrow and plug in the OBD2 scanner and see if any codes pop up. I'm not sure where gas would possibly leak since I park in my garage whenever its not driving and there is no fluids on the floor (epoxy floor)

EastBeast

Did you fill up at the same place everytime? All gas is not the same.

bigvig

SOOOOOO many variables come into play here that its next to impossible to calculate what happened and why.

Could be crappy gas, could be a heavy foot, could be crappy air quality & super hot, could be a sensor, could be crappy gas, etc. The list goes on and on and on. Unless this is a brand new issue thats JUST happening (and happening on a regular basis after filling up at the same gas station and driving the exact same way in the exact same conditions every day) youll NEVER figure it out. It is what it is really: We drive old gas guzzlers.

ScottH

I've had the Jeep going on 4 months now and only once filled up at a different gas station. I always use the same station. I really don't have a heavy foot. I drive like a old person. I'll see what think tank results and go from there. Maybe it was just a bad tank of petro.

Illuminator

Do you got a locking cap, could of been ripped off.

Slick761

^^^ loves his renix and the gas mileage it gets.

fctry286

I was acually get bad gas mileage the last tank and noticed my gas cap was not tightned all the way.

dogger15

also gotta figure if you have windows up or down that does make a difference with just my driver down its about 20 miles less than if had window up with the ac going average i get about 300 per take with 30" tires and 3" lift

blue_on_blackXJ

Unless it's gushing out, you probably wouldn't notice a fuel leak on your floor since gas evaporates so quickly. A hanging gas smell would be more indicative. My fuel pump was leaking at the fuel return line and I could sit there and watch it coming out but it never made it onto the ground (and on an unrelated note my exhaust was dumping straight into that direction for god knows how long