My first guess--the O2 sensors. How many miles on them? Also this is a fleet vehicle...How many different drivers use it? Im also guessing it gets mostly in town short trip driving...? Is it cabled or drive by wire? Can a scan tool be connected to see what's going on w/the OBDII--check for codes and view input sensor datastream. Was a re-learn done on this Ford?
Did this Ford get a significant power boost? A leadfoot driver might erase any gains. Vacuum leaks? Did the Ranger seem well maintained?
Something is Missing in Missoula!
Gadgetman Reno, NV
Re: 2004 Ranger 4.0 for City of Missoula
28 Sep 2012 06:16 #3
Do the Mod
Make any adjustments for the IAC if there is one
Accomodate the PCV line
Check for leaks of any kind
Having experimented with two vehicles, each for different reasons, I've noticed that depending on how closely to the idle position the groove is applied, the size of the groove (which bit is used) and the angle the groove is applied can create variations in the low and high end response.
More Specifically, the 2007 Avalanche 5.3L Vortec, the original groove with the large bit, the engine responded well in the 60-70mph range much better than the low end... only to be neutralized by the ECU later on. Along with that the 4 cylinder mode which would normally engage in that upper speed range began to show up in the 30-35mph range as well.
Watching the real-time mpg display starting from a light the response would be in the 5-6mpg and climb as I got closer to speed.
With the bit angle changed, this part of the response went down to 4-5mpg with a slower climb to running speed. At the same time the 4 cylinder mode also came down and was much more prevalent throughout the speed range when cruising speed was achieved. There seems to be that window in the pedal that allows for forward gains without an agressive push from the engine.
There just seems to be so many things going on depending on how the groove is placed and how the ECU responds.
IE: my other post on the 75mph MAP overlay for 29mpg.
What Tracy said about the drivers still pops up, are they continuing to drive by putting their foot into the pedal or do they realize that a lighter foot will get them so much more?