Hello ! Long time lurker, first time poster. I thought I'd share my work with my 1998 F250LD. Its 1998 4x4, automatic, 5.4l V8 and has a very healthy 243,000 miles on it, in the new body style.
Is was a bit of a basket case when I first got it in, in trade for a bottle of Jamesons 18yr whiskey ! Initial MPG showed an abysmal 7.04mpg (advertised combined is 13mpg). It had mid-matched tires, a misfire on #3 cylinder, exhaust leaks and was pretty well neglected.
Round 1 mods:
- Replace air cleaner
- Remove stock intake snorkel, install 3" intake pipe instead
- Fix misfire on #3
- Clean throttle
- Clean airflow meter
- Run full tank mixed with injector cleaner, fuel stabalizer and octane booster
12.17MPG mixed was the end result from some simple maintenance !
Round 2 mods:
- Dump transmission fluid (4 gallons worth !)
- Add Mobile 1 Mecron V synthetic trans fluid
- Dump power steering fluid
- Add Mobile 1 Mercon synthetic steering fluid
- Dump transfer case fluid, add synthetic transfer case fluid
13.4mpg mixed was the result, so slightly over EPA advertised
Round 3 mods:
- Replace tires with OEM spec
- Dump axel lubricants
- Filled rear with Redline high performance 75W140 & Delco LSD additive
- Filled front with BOSS 75W90 synthetic
12.36mpg, but all of the driving was in the city so still a bit above advertised.
Round 4 mods:
- Replace front & rear shock absorbers
- Correct swaybar linkage issues
- Adjust front ride height
13.44mpg city cycle ! 16.89mpg highway only.
Round 5 mods:
This time around I was doing highway travel to pickup a hard tounneau for the truck, so I logged the trip both ways
this was with strong head winds and a lot of rain.. and a 200lb pump in the back (delivery run)
- Without tonneau: 14.67mpg
- With tonneau: 15.84mpg
Next step I want to replace the mechanical fan with an electric one and start some aero work around the grill/bumper/skid pan areas.
TL;DR - Went from 7mpg average to 14.55mpg average with simple modifications and maintenance on an old pickup truck, 1.55mpg over EPA