Sep 21, 2015, 03:49 PM
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XJ Ask the Question Thread
CF Veteran
Joined: May 2012
Posts: 3,242
Likes: 2
From: Colorado
Year: 1992 Cherokee Sport
Engine: Bone-Stock 242
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,578
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I'm lifted 3 inches with 235's on my 1994 xj and I keep my foot out of it and I still am only getting like 150 miles to the tank. I've run injector cleaner through, replaced my o2 sensor, cleaned the TB, replaced the fuel filter. What could it be? I was looking into the tps.. Would that cause bad mpg and when I hit the gas I usually have to hammer down to go anywhere. Is this the tps? Btw my manifold is not cracked.
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Yes! On OBD-II models both upstream AND downstream O2 sensors are used to calculate fuel mix in closed loop mode. 11 MPG is pretty bad though, there's no way an O2 is your sole issue. Try searching ever other fuel economy thread and comparing notes.
CF Veteran
Joined: Apr 2011
Posts: 4,825
Likes: 2
From: Indianapolis
Year: '99 and '91
Model: Cherokee
As far as I knew, the downstream o2 was just to check the function of the cat and didn't have effect on the PCMs fuel management.
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Yours could have been fine or near-fine. They don't always croak drastically like everyone hopes. But yeah on OBD-I they're just there to set off a CEL. OBD-II is required to 'deal' with a bad cat and can sorta make up for a bum upstream O2. (There's a code thrown if US and DS are too different)
CF Veteran
Joined: Apr 2011
Posts: 4,825
Likes: 2
From: Indianapolis
Year: '99 and '91
Model: Cherokee
True. It has went on/off a few times for no appearent reason. Its on a 99 so def OBD-II
Tired of seeing that CEL so it'll get a new one when the exhaust gets revamped (when its warm)
Tired of seeing that CEL so it'll get a new one when the exhaust gets revamped (when its warm)
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
CF Veteran
Joined: Apr 2011
Posts: 4,825
Likes: 2
From: Indianapolis
Year: '99 and '91
Model: Cherokee
CF Veteran
Joined: Sep 2010
Posts: 12,692
Likes: 6
From: Mercer County, NJ
Year: 2001
Model: Cherokee
Engine: 4.0L I6 HO
Junior Member
Joined: May 2008
Posts: 15,016
Likes: 11
From: +34° 25' 35.67", -81° 21' 12.04"
Year: 1993
Engine: 4.0
CF Veteran
Joined: Apr 2011
Posts: 4,825
Likes: 2
From: Indianapolis
Year: '99 and '91
Model: Cherokee