help - extremely bad fuel economy
 

hey jp lovers,
I've got a 92 XJ and ever since I've had it parked for a year a couple of years ago my fuel economy litterally was cut in half.
I used to get 450kms out of one tank and now I'm lucky if I get 220kms. :P

So far I have replaced: fuel filter, cleaned my K&N air filter, new muffler, cap and rotor, sparks and wires, O2 sensor, coolant temp sensor, battery clamps, and I've even checked for fuel leaks...Also the engine itself had been rebuild about 5yrs ago and it runs rather smoothly, and other than needing a dire complete break job I dont know what else to do. The only thing I can come up with is the idle sensor; and none of these jobs even improoved my mpg by the slightest!

Any ideas, btw I am running 30" tires on a 2.5" lift kit.

cheers
Kat

Re: help - extremely bad fuel economy
 

I would try some seafoam in it, its available just about everywhere and can go into just about everything, but the stuff works wonders 99% of the time... id get 2 bottles

id add 1/2 of a bottle thru the vacuum line, 1/2 to the oil, and dump a bottle in the fuel tank when you gas it up

when you do the vacuum line you need a funnel that will fit into your hose, with the engine WARM slowly pour it in and when you get to half the way thru try and kill the engine by dumping a ton in, if it doesnt stall go turn the key real quick... let it sit for 10 minutes then fire it up, and that thing is going to puff white smoke like crazy... and just let it idle for a bit, then give it a few revs till the white smoke stops... then take it for a test drive...

add some to the oil when its warm, and take it out for a drive, you'll want to go up to high RPM's dont race it but let it wind itself up, it'll help break down sludge.

and the fuel tank well just pour it in and go for a spin...

it should notice some more pep in the jeep, and after that you'll usually notice more MPG. for like $15 its worth a shot...

Re: help - extremely bad fuel economy
 

have you checked the brakes......

if something is siezed than you might have some drag.... or if a brake line is pinched you might as well.

Re: help - extremely bad fuel economy
 

The only time I see a drastic change in mileage is when I'm in 4WD full time. I'm sure you'd feel it if it was stuck, but just a thought. My 97 gets 400 in town in 2WD and 200 in 4WD; I get somewhere in between with part time 4. I'm just wondering if you parked it for a year, perhaps your T-case stuck somehow and you need only go through the different settings to break it free.
I'm not sure what else to suggest, but good luck, I hope you find a fix.