So I have an 89 xj and im lookin to sqeeze every bit of fuel economy out of it I can, everyone knows xj get low mpg so hopefully everyone can benefit from this thread, I figure money saved on fuel can go back into upgrades, I know so far . . .

driving like a grandma
Removing un-needed wheight
Correctly inflated tires
Smaller sized tires help
Removing the roof rack
Proper maintenence
Clean fuel system

So im lookin for any mods, parts, hints, tricks or any info possible to boost fuel economy!

 

good exhaust system helps and clean air filter.

 

Im runnin stock size exhaust with no cat and a holly cherry bomb glass pack muffler, exhaust was completely plugged when I got it

 

Less agressive tires will also help.

 

I'd put that cat back on before you get get pulled over and in serious trouble.

 

No deq to pass where I live so im safe on that for the moment, good point to point out in the thread though, would it help performance at all to put one on?

 

Install one of these and keep the needle between 15-20, u'll get better mpg.

 

I thought fedeal law state you need a muffler?

 

Federal law says u need a cat.

 

So, its like medical marijuana, it is legal in some states, but fed law says NO.

 

Yeah, I have 31" tires on an otherwise stock 2WD 5 speed 2 door. I get 13 mpg, according to my iphone app. I have kind of a lead foot, but it still shouldn't be that bad.

I did however notice a massive increase in gas mileage when I put a bottle of the fuel injection cleaner that they try to sell you in Autozone. I got about 25 mpg instead of 13 :O but it may have been just a coincidence that worked in my favor, because next fill up, back to 13 mpg.

 

If you got 25 mpg with just a bottle of gas cleaner and no difference in driving habits, then I am Sherlock Holmes combined with Elvis shaking hands with some form of an ancient Mayan Jesus.

 

Oh I also swapped my clutch fan for an efan and it dropped my running temp and increased mpg slightly like maybe .3 mpg!

 

The importance of fresh tuneup parts should never be ignored.

For your 89, fresh Champion copper plugs gapped to .035, new quality plug wires, distributor cap, rotor, air filter.

And keep up with fluid changes. They are the LIFEBLOOD of your vehicle. Oil, coolant, transfer case, transmission, differentials. If you can do it yourself, the fluids are not expensive.

 

IMHO, get rid of the glasspack. Put an actual muffler in, the extra backpressure will do wonders for your fuel economy.