There's your problem. All the clean diff fluid in the world won't help if you're driving around with a misfire. I bet it's those silly coil packs.

 

Nope replaced them twice.

 

The Peep's over 748000 km, still maintained in good tune (original injectors, idles fine)
Sees tire sizes 27" to 31", 3:55 gear, 4.0L Renix, AW4, NP231, 3" lift.
Our basic gas here has 10% ethanol and current best price is 0.92 $/L
Takes 70+ L to fill if my tank gets low.
Get 600 km or 370 miles to a full tank.

 

Dealership, wow, den of thieves, don't enter with your wallet, talk parts counter, take advice and get a cost estimate, (remember the air fresheners are dispensing mind control drugs), look at the new jeeps, then leave for a cooling off period, clear your thoughts, shop around for parts prices, then make wise decisions, repair your XJ.
Really the guys at my local Chrysler dealer are XJ nuts with nice rigs and solid advice. However shop rate is $120/hr and they truly don't want to work on my stuff older than the WJ. Hope your local dealership will treat you right.
No matter how much diff lube you apply to those ignition coils, they won't self correct.

 

I agree I only have them work on my 04 WJ and the reason for that is it has only been serviced/repaired at a dealership from the first day it was bought. An "Overland Edition" with every option offered and every one working.

 

Reading through several threads on MPG, there are many opinions out there... On our 2001, we focused on frequent recorded tests for a baseline and total maintenance. If we completed a set of improvements, we run the set again (testing 5 fill ups in a row and document the driving conditions). Over our years of experience, we found the following improvements provided actual results:
1.) High quality exhaust system combination, Banks Torque Tube Headers, high flow Magna cats, Banks 2.5" Cat back and Bosch O2 sensors. As a package, gained just over 1 MPG from the original stock exhaust system.
2.) Using pure synthetic fluids for transfer case, axles and motor. And TLC ( tighten, lubricate and clean) for overall vehicle. As a package, gained 0.3 MPG
3.) Bosch 4 spray nozzle fuel injectors with a heat shield for the manifold and each injector wrapped with insulation (preventing the heat sink problems or mis-fires)
4.) Focus on good vehicle maintenance

With all maintenance completed (known good U-joints, wheel bearings, alignment in spec, tire pressures at 35psi, fluids fresh, clean stock air filter, no faults recording with DBRII scanner) with typical during habits ( not driving like a snail), we average 17 city and 21 highway. Note: minor lift of 1.5" front & rear, basically stock set up, auto trans & command trac t-case, axles ratio 3.55 and 29" tires. Our XJ runs at 200 F.

If we fall below the MPG averages or run higher temps, I look at what could be wrong as an indication... Seems by the many threads, there is a wide range of MPG results by the people postings, I question the very low MPG vehicles in the range of less than 15 MPG for the overall maintenance details of the Jeeps... Again, IMO MPG is an indicator of the overall vehicle condition and maintenance..

IMO, good maintenance seems to help the best for a daily driver... I stay away from the worthless improvements like after market clips or cold air intakes... Also we run only 89 octane, either Shell or Sunoco.... I tested for 89 and 93 grades, not worth the extra costs

 

Clean air filter. Correct Tire pressure. Drive as if there was a raw egg between the ball of your foot and the gas pedal.

 

Here's my 3 cents worth... A thread I made about my efforts and experiements to improve my 99 XJ's gas mileage.

http://www.jeepforum.com/forum/f11/m...5-ats-1551782/

 

Install a vacuum gauge in plain sight. Drive in the green.