Im only averaging 13mpg on the highway in my 99 2500 w/ 285/75/R16 BFG MTs. I just the truck last week and was expecting it to have better MPG. Is there any general maintence stuff that could get me more MPGs or do I need an intake, exhaust, and chip to get better milage?

 

It should get better than that stock, or modified. Did you check it by hand or on the overhead display. The overhead is not always right. Check the normal stuff, air filter plugged, need to change oil, need to adjust valves, parking brake on(don't laugh I've seen it). In my '00 I could count on 18 at least, usually 19 to 20 on the highway with the same size tires, and a manual.

 

Well I know the speedo is off by 5mph or so cause of the bigger tires. I was going by the odometer. The oil is good, parking brake is off, what valves are you talking about to adjust?

 

overhead intake and exhaust valves. any shop would be albe to perform this. Id take it to a cummins or heavy duty shop

 

When I bought my truck used it was stalk but had 110,000 miles on it and I only got 13 mpg now after bombing it I am up to 16 mpg.

 

I get 18-20 on the freeway and 12-13 around town. When towing I get 12-13. I think this is the best you can do with stock. jm.01 cents

 

same truck....as you wrangler


17 in the city stop and go...

19 on the freeway.....

15 while towing 7k boat and trailer through hills and hwy 101 on the coast.


remember if you do use the overhead...(which i agree isnt always the truest) it only averages the LAST 30 gallons since a reset.


NCA

 

I wish I could get what my overhead says which is normaly around 24 mpg .

 

If your speedometer is off then your odometer will be off as well. I wouldn't worry about it, you mileage is probably better than you think.

 

Use the mile-markers on the interstate to check your odometer. I started at one mile-marker and set my trip mileage to zero. 10 miles later I found it was off by 2 percent. So, I just add 2% to every calculation I do. If my speedo says I'm doing 50, I'm really doing 51. (50 + 2% = 51). If I'm calculating my MPG, I add 2% to the miles driven before I divide by gallons used.
You can also use a Smarty to change the tire size in your truck's 'puter and put the speedo back on track. Or the dealer can do it for some $$
We just got back from a trip to Galveston and ran about 18 MPG due to the Houston traffic.
I've heard you can clean your Intake Air Temp and Boost sensors and improve your MPG.

 

What is the ***** mean? I could just go buy a speedo gear from the *********** for $20 and swap it out. The know in my wrangler the speedo gear was in the t-case, is this the same for our t-cases? Wow this forum amazes me with the stuff that it bleeps out.

 

My 99 4x4 automatic with 3.73 (3.83?) gearing and 265 LTX's gets 16mpg, all the time, city or highway A/C or not, except when I have pulled a trailer.

For really accurate odometer checks, almost all modern GPS's are the trick. The only issue some GPS's will sense that they are moving as they continue to hone in on their exact location, and will add distance to the odometer log if they are parked for a long time (say several hours).

But for a road trip of 100 miles, nothing will give you a more accurate account of the distance traveled.

Pete

 

Speedo has to be changed with the ECM. Do you have 3:55's or 4:10 gears? How much bigger are your tires than stock? !3 could be 15 with the tires off size, and with 4:10 gears that's about right.

 

When I bought mine I got 12.5 mpg on the first tank, hand calculated. Horrified, I bought some Power Service at Walmart and put it in, maybe a bit more than advised on the bottle. I got 16 mpg on the second tank, put PS in again and got to 18.5 on the third tank. I am not adding PS in the summer, switched to 2-stroke oil, but my fuel mileage remained at 18.5.
-P