dlfrye

The fuel mileage I am getting has significantly dropped off in the last few months form a high of 16 mpg down to a high of no more than 10 mpg. The only mod I use is a Superchips tuner with which I have varied the tuning in an attempt to increase mileage but has had no noticable effect. I am currently running a "Perfect Tow" tuning setting. Any help or suggestions would be HIGHLY appreciated.

1999 Ram3500 5.9/24v 148,000 miles

stuckey200224

have you checked to see it you gettting any codes?

mini14

could be vp crapping out, does it also sound noticeably louder? timing might not be advanceing as far as it should...when i got my new vp last month my mileage went up 4 mpg and its a lot quieter. check for code 0216

dlfrye

I just checked for DTC's this evening and there are none.

Tocapet

When did you last change your oil?? I noticed that when my MPG starts dropping and the clatter sounds louder, it's time. Immediately after, the engine quiets down, seems more responsive and if I keep my foot out of it, the MPG comes back up.

2500Ram

Free mpg. Clean your MAP and IAT sensors. I've cleaned the IAT sensor several times no mpg increase, I just cleaned the MAP sensor and gained 3+ MPG towing/city hwy confirmed on 2 tanks so far.

I sprayed the MAP sensor with carb and choke cleaner inside and out and even the contacts, let it sit in the cap with cleaner in for about 5 minutes, not the contact end, sprayed it again with cleaner. Let air dry and then using less than 20psi air pressure sprayed it dry.

The IAT used a 7/8" deep well socket and my MAP used a 1 1/8" deep well socket not the 1 1/4 many have said I must have the original or the retro, not sure.

My MAP sensor was not dirty at all but there were a few black (looked like pepper) pieces sitting in the cap when I was done.

I was amazed.

Good luck.

biododge1

go back to stock on the tuner. i had the same prob on mine.

dlfrye

Oil change has less than 2K on it so I don't think that is a the problem, but, hey, thanks anyway. I try to keep my foot out of it most of the time. My pockets aren't deep enough with the price of diesel!

dlfrye

I'll check IAT and MAP sensors this weekend. Thanks for the suggestion.

dbartran

I have a 2000 - 3500 auto, I want better milage, who knows which chip I should use. I'm not interested in running the 1/4 mile or pulling the empire state building over a couple of inches, I just want a little more power and a few miles more MPG. Can anyone advise me on what I need?

Danny

cohocoal

I can't/won't give advice, I will say from experience that after I installed the diablo puck I was delighted at the performance improvements, particularly at mid range RPM's. My wife reports that after 2 tanks of fuel pulling our 3 horse trailer ( goose neck ) the mileage improved from 13.2 mpg to 15.2 mpg. I haven't determined the truck only fuel economy as I can't always keep the lead out of my foot. It appears as though the 2 mpg increase is constant regardless of load/work demands.
My experience only.