kawazuki650

So I am a consistant 10mpg. From what I have read doing searches I should be around 15-18 city not 10. It is a rebuilt engine with about 5000 miles on it, 31's, flowmaster 44 and a snorkle. With the snorkle and free flowing muffler I should be getting even better than 15 but I am not. Any help as to what could be the problem would be great. And I have a sport bike for going fast my XJ I drive like a little old lady, drives my wife nuts, so it is not a case of being heavy on the throttle.

freegdr

when was last tune up

mwdouglas

has it always got 10 mpg? did you buy it with the 31's on it or put them on it?do you know what gears your running? i have 33's with stock 3:55 gears and i get 12 in the city and 15 on the highway mine has 2.5" exhaust with a homebrew cold air intake and still only get 12,15 mpg's i drive the speed limit take off from dead stop like a 90 yr old man and only run 65 on the highway

kawazuki650

What do you mean by tune up? I have changed the oil three times, new air filter, new plugs and wires since it was put in 5000 miles ago. What were you thinking in terms of tune up?

kawazuki650

No it has not always gotten 10 mpg's. And yes I put the 31's on when I put the engine in. Last couple of winters I was getting around 14-15 mpg's. I only drive it in the winter as my bike is my primary transportation. Not sure but I think its 355's

00jeepXJ

I saw that you were new and want to say Welcome to Cherokee Forum... how did you go about your gears? Like another person posted here if your gears aren't right you will suffer in mileage. Also was this a reman engine or did you rebuild it yourself? Sometimes ( not always ) the reman engines need to be broken in to get them to where they need to be. The tune up portion is just new filters, fluids, plugs and wires.

kawazuki650

Gears are what ever came stock in 1990 and the engine is reman.

mwdouglas

there prob 3:55's as far as why the drop in mpg's im stumped at the moment it was getting good mpg's as is then all the sudden it dropped hmmm by chance did you change were you purchase your gas i know if i get gas at certain stations here local i get worse mpg's

alloutperform

hell you getting the same mpg as my 468 cu.in. bbc in my shortbed chevy. lol. what kind of tires? i gained 4 mpg going from 31in swampers to 32in bfgs the tires then destroyed the milage on my girls wrangler going from 22 to about 15 (4cyl w/ 235/75/15s)

alloutperform

coolant temp sensor can make it run rich and thus hurting mpgs

bikerider

auto or stick? yes it does matter

mwdouglas

yea auto was 3:55 and stick was 3:07 on most

EVcherokee

10MPG's?! Dude, take the E-brake off!..joking!..

Welcome to the Cherokeeforum!

I'd seriously suspect a bad O2 sensor. Theres a lot of contaminates that go out the pipe when a motors breaking in and O2 sensors don't like that stuff. Depending on what kind of rings the rebuilders used and where they put their tolerances, the motor might still be a little tight, but at 5K things should be broken in. If the O2 sensor isn't it, I'd do a full diagnostic of the fuel system, because it should be keeping your A/F ratio at 14:1, which will give you 10mpg if your towing or beating the pedal like I do my kids.

How's the exhaust smell when its warm? Does it blow black when you mash the skinny?

rich

Try giving it a while to get broken in if it s only got 5000 miles on it everything is still quite tight.

kawazuki650

First off I gotta say WOW!!! I have belonged to many forums over the years for my sport bike and have never got as many helpful and rapid replies Thanks guys. It is an auto, no black smoke and it does not smell rich to me. You guys gave me lots of places to look so I will see what I can find. Thanks agian