what kind of milage

[lenweiler]

I'm looking to buy a '99 4X4 quadcab long box with 24 valve head. It's got 354 gears and the auto. What kind of milage can I finally expect to get.

[ol ron]

I get 14.7 in town (horrible traffic, lots of stops) and just under 21 at 70MPH on the road. Altitude here is 3800 feet. You will not be sorry you bought that truck! I would NEVER go back to gasoline power. Nothing like a Cummins.
Ron

[lenweiler]

Thanks. Nor would I. This is my second. But I do find that the steering is tempermental. It oscelates back and forth. This is my first 4X4. Is this typical in the '99's?

[ol ron]

is a problem with some 98-01 4X4's. I have never experienced that symptom, nor brake pull. Mine handles very well, especially with all the back road stuff I do. I suspect that you might have a worn track bar joint. The whole track bar must be replaced to fix it. Steering gear boxes have some failures too, so I,d have a good frame/alignment shop go over it for you.
Ron

[lenweiler]

Thanks. I'll have it checked.

[gotcha]

Lenweiler...I have owned 5 Cummins Diesels to date. I put about 50M miles per year on them. We do numerous shows and races, and being in the very bottom of Texas.....anywhere is a long trip. My 99 24V 3500 Quad Cab Dually (not 4 X 4) gets and has never gotten over 19 on the highway....(3.54, auto), but gets 15.5 in town and about 14.5 pulling a 40 ft. Gooseneck with a total weight of 13005# (trailer only). I have always been disappointed in the empty highway mileage, but really pleased with the towing mileage. I have owned 3 autos, all 3.54's, and 2 five speeds...all 3.54's. I had a late 91 (intercooled) five speed that would get 23 empty and 17 towing the same weight. That damn thing was an animal. Best I have had. New HD-6 speed ordered. Drove the auto and was disappointed, but the HD with the stick was very impressive. I always use the K&N filter with no other mods. The above numbers are with cruise set at 68-69 mph and about 1850-1875 rpm.

[lenweiler]

Thanks for the reply. A word of caution on the K&N filter. Someone on this site I believe cautioned agaist it's use because it may screw up some sensor. Could your poor milage (empty) have to do with your speed since the turbo is probably comming in at higher speeds?

[gotcha]

Lw.....could possibly be the speed, but am on boost at about 1600 rpm on all of them. The 24 valve is real happy at about 1900 to 2000, but the mileage does not vary. The real problem with the autos is the massive slippage in the converter until lockup in OD. The Cummins and the stick are the mileage champs. I will keep this truck as a spare and really plan to work with it after the new one is here. Gonna try the billet converter and the Blue Chip. Have not had any trouble with the K&N's on any of the trucks, and always show about 1 mpg gain on economy. Have never had a maintenance issue with any, but just replaced the lift pump on this one. Very common problem.

[fox]

The issue with the K+N filter is not a K+N problem, it is the oil used to assist the filtering.
Some people may have over oiled it. Some also prefer to use the high tac oils that are used for motorcycle filters.
K+N has a good product and most people report a slight improvement in MPG when using them.