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Terrible gas mileage! Maf sensor?

M

MrAnderson

NAXJA Forum User
Location
Arroyo Grande, Ca
So I'm getting pretty bad gas mileage in my 2000 xj sport. Doing the math old school came up with 11.5 the first time and then I put a intake and Flowmaster cat back it went to 8.5( I did a bunch of beach driving though) a friend sai I should check the maf sensor... Where's that haha?
 
How many miles? Plugs been changed recently? Coil packs functioning properly? Injectors clogged? Fuel pump/filter ever been changed? O2 sensors been replaced?
 
Do you have larger tires? If so did you correct to speedo yet? Throwing any codes?
 
You have no MAF sensor. That's another system entirely and not used on your Jeep. He' just guessing.

Tune up parts need to be fresh. Basics have to be covered.
 
May I suggest running some MMO, or seafoam in your fuel tank next time you fill up.. add it before you fuel up, of course, so it will mix better.
 
Seafoam is definitely better. I always have at least a QT of MMO on hand, as you can use it for pretty much anything.. cranckcase oil, trans/t-case fluid, in your fuel tank etc.
 
If you experience an unexplained drop of 30-40% in your MPG's, suspect a faulty O2 sensor. If you have a 1999 and older also suspect that you have a cracked exhaust manifold.

Are all your preventative maintenance and tune-up parts fresh ?


SeaFoam/MMO/STP is not going to fix 11.5 MPG's.
 
Tim_MN said:
If you experience an unexplained drop of 30-40% in your MPG's, suspect a faulty O2 sensor. If you have a 1999 and older also suspect that you have a cracked exhaust manifold.

Are all your preventative maintenance and tune-up parts fresh ?


SeaFoam/MMO/STP is not going to fix 11.5 MPG's.
Click to expand...

I'm currently looking into replacing my o2 sensor. Anyone know I link to a good write up involving where the heck that is? :)
 
the O2 sensor you need to change is just below the exhaust manifold, beside the trans bellhousing, unless you have the 2 precats then you'll have 2 in that general area.

the one out by the muffler doesn't affect the engine performance ... it just throws a light to signal the cat is not doing it's job.
 
Devilfrog said:
the O2 sensor you need to change is just below the exhaust manifold, beside the trans bellhousing, unless you have the 2 precats then you'll have 2 in that general area.

the one out by the muffler doesn't affect the engine performance ... it just throws a light to signal the cat is not doing it's job.
Click to expand...

Yea I spotted four of them, buried hella high up on the pipes where it'll be a PITA to get to from both above or below :( f my life. I'm guess the 2 ur refering are the furthest ones that are right besides the block?
 
standard.jpg
 
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