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Sudden mileage drop
- Thread starter Brutussr
- Start date
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
MadPikAvenger
NAXJA Forum User
- Location
- Michigan
Tire pressure and alignment can make a difference as well.
wishbone
NAXJA Forum User
- Location
- Carbondalahara
exhaust manifold
Mudderoy
NAXJA Forum User
- Location
- Katy, Texas
I read an online article where they were trying to get the most mpg out of an XJ. All of the sudden the mileage took a nose dive, then the power steering pump froze up a few days later. They replaced the pump and the gas mileage returned.
TerraWombat
NAXJA Forum User
- Location
- Eastern Shore MD
I've only had my XJ for a couple weeks now, but I've been monitoring the fuel consumption. Even with all highway miles (traveling around 70MPH) and no A/C on, I get about 16-17 MPG. I was under the impression that the 4.0L was slightly better than that on the highway, but I could be wrong.
I quoted your post in particular because I do know I have a slight exhaust leak at the flanges between the header pipe and the intermediate pipe. I personally don't see how, but could this be a possible cause for decreased fuel efficiency? I don't know the condition of my oxygen sensors, so I should probably start there first, but was wondering if my known exhaust leak issue could be a cause.
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Any exhaust leak upstream of the o2 sensor will indicate a "lean" engine condition, the ECU/PCM enrichens the mixture = lower MPG.
wishbone
NAXJA Forum User
- Location
- Carbondalahara
This^ is true. I ve done three Manifolds on 2 jeeps now, and everytime they go, I go from 18/20 to 13/14. after replacement, back to 18/20.