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I have had my 02 Durango for a little over a week and gas mileage is bad (Not complaining, I love the 5.9!!!). I am just looking for opinions on what mods make the best MPG increase without loosing hp or torque (cold air, exhaust, synthetics, ignition, full tune up, etc.). Any numbers you can give would be great. As a start my tires are properly inflated and my foot is lighter, most of the time.
 

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I have come to realize that owning a 5.9 comes with the high cost of poor fuel mileage. There are some add ons that will show some improvement but you need to weigh the costs of the add on vs. the increase in mileage.

Simple items such as a set of good spark plugs, brass cap and rotor along with a set of good wires such as the new Taylor 8.2mm is nothing more then the cost of upkeep. In other words your going to buy these items sooner or latter so you might as well buy the good stuff.

A good syn. oil comes at a premium cost but it does afford you better mileage and gives you some added insurance in the engine wear department. I don’t think that anyone can go wrong with using a syn. oil, just don’t expect it to give you a huge increase in mileage, you may see 1 or 2 miles per gallon.

The cold air intake does help some, I am getting about 2 more miles to the gallon with my 360 Air and it is easy to install. Some say that by relocating the IAT helps increase mileage and gives you better throttle response. I tried this and I have not seen any improvement at all. I am hearing that the throttle body spacers increase mileage but I think that the jury is still out on that one.

The biggest bang for your dollar is opening up the exhaust. A good duel system and headers will give you the most increase but you may loose some torque if you go too far. This is also the most expensive change that you can make, expect to pay around $400 to $500 for a good set of headers and another $500 to $800 for the duel exhaust.
 

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Don't scoff at 1-2 mpg increases. That's a 10-15% increase which is good in anyone's book. If we all suddenly got that kind of increase, gas prices would plummet.
 

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Discussion Starter #4
any more suggestions mods or numbers? I am mostly looking for performance mods that will offer the greatest power increase along with a good mpg increase. I have about $400 left in the immediate budget for my stock '02 rango 5.9 slt.
 

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what about a fastman TB?

that and the superchips with be my next mods.


otherwise weight reduction would be your biggest friend...and its free.
 

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You already know what the cheap mods are. You could also try advancing the timing via the crank sensor mod. Forget junk like TB spacers.
 

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All the "numbers" are not in yet, but here are some things I did "on the cheap" for my '96 4x4 extended cab long-bed (heavy) with 3.9:

NAPA "brass" dist cap and rotor: $14
MSD Blaster replacement coil & Taylor 8 mm wires, Truckpermformance: $100.55
Clean and oil K&N filter: $0
38 psi in all tires: $0

Total, less than $120 including tax and shipping where applicable.

MPG in-town +3 mpg (12 to 15) --25%--BEFORE wires installed and air cleaner service.

I have been checking mileage on one tankful after each change I made. Increased about 1 mpg after the new dist cap and rotor, 1 mpg after coil, 1 mpg going from 34 to 38 psi.

I drive pretty much the same in-town routes at similar speeds between fill-ups, so the figures should be fairly accurate comparisons.

My plugs are the standard Champions, and have a few thousand miles on them.

I'll post the final in-town figures--with new wires and air cleaner service--after I fill up this week, and later when I get some all-highway miles in on a tankful. (Running 87 octane unleaded.)
 

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taking your truck on a long drive here and there will help get better milage too. i drove to my brother in law's college to help him move across town, it was about a 200mile round trip for me. thats from my place, to my place. i now get average of 2-3 mpg more.
 

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HAHA looking to do performance mods and get better MPG?? wont happen lol....it might make the engine run more efficent but youll never keep your foot out of it especially if you get an exhaust. (TRUST ME!!) But about 2 weeks ago i switched my rear end fluid with mobil one synthetic and was seeing about 11.5 mpg. before and now my overhead says 11.9 and I havent changed the way I drive it. (Only got a 5.2 so dont complain about your 5.9 gettin that bad of gas milage!! lol :joke: )
 
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