Driving home tonight i decided to play with my trip computer. I set the cruise at 60 on a local highway. I figure about 15-20 miles with some hills and flat spots. The lowest my computer flashed was 23.1 while the highest was 24.7 Most of the ride it was around 24.4 or .5

 

it would be interesting to see how far off from a hand calculation it is. mines 3.8 mpg high compared to the hand calculate numbers over 400 miles

 

I hope its not off by much. My computer reads 11.5-12 around town. If im getting under 10 it would be time to sue someone. Epa is supposed to be 14

 

I'm sitting between 14.3 and 14.6 with 50/50 highway city with a 5.9, so when I see 24 I'm stunned! But Those tripcomputers are not all that accurate, given I'm basing this on my experience in a GMC Safari, it was off by as much as 15%, even then, you're way ahead of me.

 

Mine is usually reading about 0.5mpg high, and never anymore than 1.0mpg high. It has gotten a lot better than when it was new.

 

In my opinion is it always a good idea to do a steady 60 mph test run for MPG when you know that everything about the truck is working correctly.

Later, if you suspect a problem has developed, re-doing the steady 60 mph MPG test is the most sensitive test you can have to see if things have indeed gone bad.

It is also valuable to know the surprising numbers that a Ram pickup can get at a below average 60 mph speed. Nothing else can show you how the aerodynamics effects a pickup truck. After doing the 60 mph test, do a 80 mph test on the same stretch of highway and compare the difference.

more aero information:

http://makeashorterlink.com/?B24115BAC

 

My experience has always been that those computers give lower than actual fuel economy. In order to get a semi-accurate mpg rating, you must check it after quite a few miles have been driven. They inflate at first if you are on the highway and deflate way too low if you in the city.

 

Keep in mind that the computer works off of averages. Restting the mpg and driving a short distance on the hiway will make the averages look that much better.

 

I'm with the other guys, don't put too much stock in those things. We had one in a VW Passat that was actually dead nuts accurate (never was it more than .3mpg off), but you gotta hand calculate to know this. And, a hand calculation will always be the most accurate way to get your mileage.

 

I get 15.7 if I don't give it gas hardcore, and normally I get around 14.9-15.1