need help
Thread Starter
Senior Member
Joined: Aug 2011
Posts: 607
Likes: 0
From: pennsylvania
Year: 1999
Model: Cherokee
Engine: 4.0L
I'm getting 11 mpg and I can't figure out why. I have a 99 xj sport with 206k and I have just recently changed the oil, oil filter, and transmission fluid and filter for that too and nothing has helped. Have also tried running injector cleaner through it and nothing. Any help would be greatly appreciated cause I can barely afford to put gas in it anymore.
Junior Member
Joined: Jun 2010
Posts: 35
Likes: 0
From: Midwest Arkansas
Year: 2000
Model: Cherokee
Engine: 4.0
OBDII Live Scanner
The best place to start with low fuel milage is to look and smell for a fuel leak. If you can't find a leak then use a OBDII Scanner that allows you to check for a failure code and view live emissions data. I would start by monitoring the primary & secondary (if applicable) O2 sensor voltage to see if it's working properly. Monitor the engine temperature. Then watch to see if the system will change to a "Closed Loop" mode after the engine warms up. If it doesn't change to Closed Loop then it will continue to run in "Open Loop" which will use considerably more fuel, then troubleshoot why it's not changing to Closed Loop.
If you don't have a OBDII scanner that does this, check around with your buddies to see if they do. If you have a Laptop Computer you can purchase software & hardware from several different places ie...AutoTap, ScanTool etc... just google "OBDII Live Scanner". Or if you have a smartphone you can get the Tourqe App and by a bluetooth adaptor for it. Using a scanner and a multi-meter greatly enhances your chance to find a problem without spending money on unessessary parts.
I know this is not the answere you were hoping for but if I were to tell to change this or that without knowing a lot more information it would simply be a wild guess.
If you don't have a OBDII scanner that does this, check around with your buddies to see if they do. If you have a Laptop Computer you can purchase software & hardware from several different places ie...AutoTap, ScanTool etc... just google "OBDII Live Scanner". Or if you have a smartphone you can get the Tourqe App and by a bluetooth adaptor for it. Using a scanner and a multi-meter greatly enhances your chance to find a problem without spending money on unessessary parts.
I know this is not the answere you were hoping for but if I were to tell to change this or that without knowing a lot more information it would simply be a wild guess.
Last edited by Apostle2; Nov 2, 2011 at 06:43 PM.
Newbie
Joined: Nov 2011
Posts: 1
Likes: 0
Model: Cherokee
have a 97 gr cherokee, i replaced the fuel sending unit because i had a fuel leak coming from on top of gas tank, leak was the same. then i replaced the pressure line right off the fuel sender about 15" worth, piece right from jeep NEW leak is still the same what to look for. or is there a simple remedy?