2002 Limited (V6 gas), basically stock and original. It has always gotten bad mileage (12 ish city, 20 highway) but that is with the wretched alcohol diluted gas we have to get in illannoy. With real gas its more like 13+/22, still pretty bad.
It was in for mileage several times through 2004 and had the computer reflashes done then. In the last year it had the front pipes and lower cat and the muffler replaced. In spring after running a tank with Sea Foam and doing 'the treatment' with it I replaced the PCV valve, spark plugs (with E3s that I got on sale based on numerous recommendations), an AMSoil air filter, and new thermostat (factory temp). I also replaced numerous vacuum hoses under the hood to clear an error code. Its been getting Mobil 1 for 5 years, and had its last change in late winter, currently 2800 miles ago. I did the ECU clear (pull the battery and draw down power so it resets to default and 'relearns' after doing all the maintenance work and drove it around town about 2 weeks before a 900 mile round trip.
Coolant (old and new) is clean and clear, oil is good, no sign of blow-by or leakage between oil and coolant. Trip mileage was low (16-17mpg) but I did have a Surco roof rack on it so its not representative. But now in town I'm down to 11MPG (roof rack off and lightly loaded) and there's a stumble or miss when in a high vacuum state decelerating. IOW when I let off the gas and start coasting I can hear and feel the engine stumble a bit. No problems at idle or while accelerating.
My scantool (KalEquip/Actron 9615) shows no problems, no codes. When I record a few minutes of operation (this tool can record and review but not dump to a computer) nothing looks out of bounds but I'm far from expert on that.
Tires (stock size Geolandar HTX) are at recommended pressure. I'm certain the car is not getting gas stolen, at least not on any regular basis.
Any thoughts on the deceleration stumbling, or the fuel economy appreciated. I'd love to get this Jeep up to the 15-18MPG so many report getting in town much less the mid 20s on the freeway. Would it be worth taking in for another ECU or trans controller reflash (its been 6+ years)? Could the E3 plugs be the cause of the stumbling under just that specific condition?
Rich
_________________ 2002 Liberty Limited 4WD, 3.7l V6
Steel Blue/Taupe
Selec-Trac, Offroad Group, Trailer Tow Group
1971 Dodge Challenger, 318cid, A904 Torqueflite
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