Nakedginger

Hey,

I know the XJ is not built for its gas mileage, but the past month or so it seems that the mpg has gone down. I have a 1990 2 door XJ with 4.5" of lift in the back, around 3.5" in the front, after market bumpers, a straight six, and 31 inch new Goodyear Duratrac tires. I've been resetting my trip gauge the past couple fills and have been getting around 200 miles per tank. I say around since I don't run the tank till its empty so when I fill up its close to 200 miles. That math comes out to be around 10 mpg. Is this normal for a 4" lifted XJ with 31" tires on it? I have just been driving around town doing this and that for most of my results.

Thanks!

jeeponblocks

I have a 1998 that is a daily driver no changes from new it runs 18 mpg /20 mpg. Pulling a 16 ft travel trailer down to Texas 3000 mile round trip it averaged 12 mpg. I believe you should be running at least 12/15 mpg if you are not hot rodding it!!!

ckysodkorn_xj

time for a tune up =)

salad

On a 1990 the "tune up" list is quite extensive. Hop to it!

I'll let cruiser54 chime in with some part numbers on spark plugs and O2 sensors. A fantastic place to start is his "Mostly Renix Tips", which you'll find in the writeups section.

doc_

Not to be a smarta** but you said about 200 miles between fill ups. Reset trip and fill up and when you fill up again take miles on trip divided by gallons pumped That will be your real mpg

cruiser54

Renix tips first.

Plugs, wires, cap and rotor. NGK plugs, Napa Belden wires, Premium cap and rotor with brass contacts. Oxygen sensor if you never replaced it.

Nakedginger

I will check all these and make sure the connections are good, but about 13,000 miles ago I replaced the existing wires, cap, and rotor with new parts. I also last weekend took the cap off and cleaned the brass points inside and cleaned the connections on the the rotor. I also got electrical cleaner and took each distributor wire off and sprayed them all down inside and out, cleaned the connections on the spark plugs, cap, and then re-installed them. My next plan of attack is to make sure the plugs are still good and that the gap is correct.

I remember about a year ago my dad and I played with the O2 sensor. I usually ,when I replace a part, record the mile mark for the car and what I did in a booklet I keep in the glove box. When I looked at it I don't see that we replaced it. So Ill have to test the O2 sensor and see if its working or not.

Thanks for the input!

I also have a trip meter going right now on the tank I have and will make sure what I am thinking the mpg is, holds true to this tank.

cruiser54

Good job. Now go to the Renix tips and get er done.