$$DIESEL$$

I have a 99 3/4 cumming and im only gettin about 13 to 15mpg! What is the average cause i talk to a guy that has the same thing and he is gettn 20! It dosnt feel like its pulln right either, i have had it hooked up at 4 dif places around oklahoma and they have no idea what up wit it there sayn the comp says its fine? ANy ideas!!??

[muddybronco]

every time i run into a guy in a cummins i ask him how he likes his truck... they all say mileage is over 20 on the highway unloaded. if you have low gears in the rear you probably wont get that kinda mileage though, and i hear duallies get slightly less mileage also. i know diesels start sucking back on fuel above 2k rpm or so... where does your tach stay when you're on the highway in OD? or is that city driving? it might be a clogged catalytic convertor or maybe a tranny problem if its automatic.

[superswamper]

Its the older 12 valve cummins that got the good mileage, the new 24 valve motors I heard got around 17???

24 Valves use more fuel than 12 valves do, and in 98.5 Dodge made the (bad) swap to the 24 valves. So your 99 has the 24 Valve, and watch out because the 24 V's go through lift pumps fairly often. You didn't specify 4x4 or 4x2, manual or auto, but with 13-15mpg I'm gonna guess its 4x4 auto. Automatics also get a little less mileage than manuals do.

One thing you need on a 24 Valve <font color=blue>Cummins</font color=blue>(not Cumming) is a fuel pressure guage, along with Boost and Exhaust gas temperature guages if you tow a lot. Also if you truck is an auto and you tow regularly invest in a good tranny cooler. It will pay for itself because Cummins love to eat up Automatics.

I don't tow very much with my 97 but I still added the Boost and EGT guages to key and eye on the motor.

A good site to check out is <a target="_blank" href=http://www.turbodieselregistry.com>www.turbodieselregistr y.com</a>. It cost's $35 a year to join, but its well worth it. You can go through and read the discussion forums without being a member, but you won't be able to post. Look for my username "Got Smoke?"

[72geepee]

16 to 18 mpg in town 20 to 21 mpg on the freeway unloaded , 12 mpg in flat ground pulling a 30' 5th wheel. 99 with auto and 3.50 gear ratio.

[superswamper]

Hey bogger101, with you having that name, do you ride on 44" boggers? b-101 is the product code for 44/15" boggers. I miss my old 35" boggers, damn things worn out to quick on my 2500...:-(