I have a 1994 Cherokee 4.0. Automatic. Stock tires and suspension. Around 200,000 miles on it. In the past 6 months I`ve upgraded my intake manifold to one from a 2000 Cherokee. Have a cold air intake on and have the EV 1.3 4-hole injectors. I am getting about 20MPG on the highway which is pretty good but my city MPG is a horrible 10.5! Can any of these "upgrades" be the cause or should I possibly look elsewhere? I have no trouble codes or anything showing.

 

Shut the engine off at stop lights and go easy on the gas pedal, my only advise.

 

k&n air filter

 

k&n is one of the best things, making sure your fuel filter is replaces every 20-30k also make sure your cat. isnt clogged.

2¢

 

I have the same problem with my 2000 XJ. I think it has to do with how hot the engine bay gets when sitting in traffic. When your on the high way, as least the air in the engine bay is moving a little bit. I'm going to install some hood vents. It might help slightly.

 

well i get 24 on highway and my city sucks too but i drive it like i stole it though cause i love the way my engine roars so that may be my problem.... do you that may be it if so drive like him >

 

hmm, i get 18 on the highway in my '99 GC. i'll check my filter out..

 

Is the terrible gas mileage a recent problem? My XJ had 2 fuel injector leaks. Not sure yet how it affected my mileage. Last I checked I was getting 13.5 in town. I haven't checked since the problem has been fixed. 10.5 is pretty bad though.

 

defiently get your catalytic converter checked out and get a louder muffler put on while your at it
if your cat is bad it'll be casuing restriction and a more free flowing louder exhaust will let exhaust out better on your acceleration.

 

Hmm, this seems to be a pattern with alot of us. Terrible mileage for seemingly no reason. I have very much altered my driving, and coast in nuetral a lot. Everything except the fuel filter is check and I can now only get 15.5 max. Half and half.

On 2000 models, since the filter is in the tank, how would you go about replacing it? Would it even be worth it? Can it cause that bad of gas mileage without any other symptoms?

 

You sit at a stoplight with the engine running, you're burning fuel but not moving, so the mileage will be low. It's not the under hood heat, or any of that crap. The Prius gets super high MPG in the city because the engine shuts off at speeds under 25MPH. That means the engine is not burning any fuel while sitting still. City driving requires you to constantly accel and decel up to hundreds of times in a short amount of distance, that burns more fuel.
The cash you spend on a K&N filter is wasted if think you're going to make any kind of gains. Keep the engine tuned, run a lighter oil, keep the tires inflated, and drive like your grandma if you want to save gas. Oh, and keep all of the heavy junk out of the trunk, that will help too.

 

i wouldn't think his cat. converter is clogged. he said he gets decent mpg on the highway.
hey programbo, what kind of mpg did you used to get in the city before your upgrades?

 

If I recall right my city MPG was up near 13-14 before...Maybe just age on things?

 

Have you tried drafting the car in front of you? (But I believe the police will call it tailgating)

 

it might be your "cold air intake". most of us have cold air intakes stock. when you remove them and put in an exposed filter its not really cold air your getting unless you pay the big bucks for one of those after market kits that come with the walls you put into your engine bay and it makes its own little blocked off filter area. if you only have the tube and a round filter, you have a hot air intake. that might be your bad choice. it will work great on the highway because of the moving air but in the city it is just sucking up hot engine bay air. the factory box is only open to that slot next to the lights so its getting colder outside air instead of engine bay air.

but 10 mpg difference is alot, even for an intake. i would look at stuff like your bearings, make sure your brakes are not dragging, get an alignment, stuff that actually puts drag on your drive train. maybe you have a multitude of little things wrong like distributor cap and rotor plus air pressure plus alignment, plus this or that, and that? you never know but it might just need a full going over.