What's getting good mileage is this 11 year old necro thread.

 

There will NEVER be a Honda in my driveway. Ever. Currently 4 Dodge trucks here
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the suggestion listed here for tire inflation, will only serve to wear the centers of the tread out to nothing with still seemingly plenty of tread on the edges. when they made the tire, the tire mfr had no clue what it would be used on. You DEFINITELY don't want to do this if you run higher load range tires...… the Durango don't weigh any more with P rated tires on it than it does with load range D or E. which say on the tire 65 or 80PSI, respectively. any fuel savings will be spent on buying tires more often.
Several have been trying to talk me into a computer flash, of which I have been reluctant to do. Currently my engine is dead stock, but heads have been replaced with EQ's, when this engine was put in a few thousand miles ago. also have 4.7 injectors, were a must/ as that's all I had around, and a couple of stuck injectors was what killed the original engine. (washed out the cylinders/rings) 138k on engine in it now (262k on body) I have a set of 1.7 RRs sitting here, and a set of stainless shorty headers (IDK what brand, but they have never been mounted and found them for a steal on CL.....) and I am looking to put these parts on (got the RRs and hardened pushrods from a buddy that built his 360 in his pickup into a 408 and went a different direction with his valvetrain than 1.7s afterwards-- so he gave those to me) daily driven, about 60% open road, 40& in town stop and go... most of that 40% driven "softly" by my wife.... I occasionally pull a trailer with it..... plan to run the wheels off of it.... looking to see what "tunes" I can get, to max out power and mileage.... I know it will never be great on mileage but want it "the best it can be for what it is"..... his thing did surprise me with fantastic mileage (for what it is) around 20 mpg with the original engine still in it, on a road trip we took to Houston.... seems like it did its best on MPG on the miles I drove on gas bought outside my home state (Illinois) as weird as that may sound.

 

02 Dakota 4.7 Quadcab, 4X4 180K miles I just changed the ORIGINAL plugs on my 4.7. The electrodes were not even stubs. Amazing though, the engine always stated with just a click of key, ran smooth, idled at 500 on the tach with no vibration, passed emission but gas mileage has always been poor, I begged for 17mpg on the highway across Kansas. I track gas mileage with every fill up. I am anxious to see if millage changes. Truck always had good power out of the hole but not much past 60 mph. I pull a small 1500lb popup. Really not much extra power at highway speed.

I removed the intake filter to get easy access to the spark plugs. There is a black tar on the throttle body right after the throttle plate. What is that stuff? Where did it come from? Is it worth getting ride of?

I attribute the engine running great with no electrode left to the coil on the plug. That technology must be amazing.

 

good gas mileage outside of Illinois my be too less ethanol in the gas. I have never any better than 17 on my4.7 Dakota 4x4

 

Yeah, cleaning out the throttle body really wouldn't be a bad plan.

 

Any performance improvement will not pay for itself.
I found that when my coasting (65mph, downhill) would NOT show 30 mpg and better, a front O2 sensor restored that and potential for 21 mpg hypering. My theory is O2 not bad, just poisoned enough to always read high and call for more fuel.
I do the math all the time, trucks this capable are not yet worth the money in payments.
Enjoy your $600 truck, drop the collision, and daily drive something else!

 

My 5.9. I will never see anything north of 13-14 mpg on highway. At times, I may best at 16mpg only if trip is totaly on level roads. 10-11mpg in town. 5.9 are thirsty beasts. Then again, with performance upgrades, that did not help much either. Mostly the 4spd transmission takes alot of mpg out as well. not very efficient.

 

I suspect you could do better than that..... I used to get those kind of numbers with my 3/4 ton truck...... I would be tempted to go back to the standard copper plugs, (the rare-earth plugs tend to cause issues on these motors) and unless your tune specifically states it, go back to the 195 degree thermostat. How old are your O2 sensors? If they are still original, I would be real tempted to replace at least the front O2..... (NTK or Denso sensors only please.)