No matter how steady I drive it and tune it my 2002 ram 1500 average 11 city and 13 hwy. I don't know what's my real EPA is I look up it does 13 city and 18 hwy but I don't get that EPA mileage. I highest I got was 13.6 and that was mostly freeway. No I don't press down the gas I use cruise control when the road is straight. I add flowmaster 40s, KN drop air filter, use synthetic motor oil, replace spark plugs, and flush transmission oil. It had 17 stock rims, i replace it with 20' inch rims. I know is a big truck that weights 6600 lbs but getting that low mpg really discourage me especially when gas prices rising again. What's wrong it or is the 4.7 too small?

 

Well idk who told you your truck was 6600 lbs but thats untrue. It should weigh in the neighborhood of 5000-5600 I believe. As for your MPG problem you probably need an engine tune up, like a clean out of the whole system. How many miles are on it? The 20s killed you mileage a little but not 5 mpgs worth. You could check your tranny and diff(s) as well. They might sap some mpg with dirty, old fluid in them. The 4.7 generally gets about the same mpg as the 5.7 and I get 17-18 hwy easy

 

It barley has 99200 miles on it, I haven't driven much like I use to only when I go to work. My job is part time job say 2-3 days a week so that when I drive it and is mostly hwy. I always assume 6600 cause the sticker besides the drive door say it.

 

That's the max recomended weight from the manufacturer. Truck should weigh anywhere from 1000-1500 pounds less than that. Now for MPG, if you don't have monster tires on those 20's there has to be something wrong. I assume you've double-checked the MPG by hand and not just the overhead as that could be off some. I run non-highway friendly gearing and running around 70-75mph, I've never seen anything less than 15mpg when it's windy.

 

2wd or 4wd, what gears?

 

Your statement regarding 20's is completely false. I just went from 17's to 20's same exact outside tire diameter and I have gained fuel mileage as will almost everyone. Less tire equals less weight and less mass to start to rotate.
Now to OP the 4.7 does not get much better than a 5.7 however I have a 5.7 4x4 and I get 12-13 in city and 16 on the hwy so not to far off the marks. Sounds like you just dont get great gas mileage. You could unplug the battery for about 10-15 minutes to reset the computer and then try and baby it as the computer relearns your air fuel mixture to tune it to your driving but good luck. Also my truck weighs in at 6100lbs so not sure whos is weighing in at 5400-5600. Just check the sticker ont he door and it will tell you what it weighs.

 

I have a 03 4.7 single cab with stock 17 wheels. I do also have a chery bomb extreme exhaust and i average about 11.5mph mostly city. I utilize cruise control a lot for city driving and keep my rpm below 1500 cruising or below 2500 if accelerating. Seems to be about typical. I did notice when I had got the truck it had some really nice good year tires on it and I was pulling closer to 13 mpg with it but when I put on Firestone tires and when i noticed the drop in mpg.

 

The sticker on the door is not your actual weight. Its how much you can weigh when fully loaded down safely. And YOUR statement about 20s is false sir. You're going to tell me that 3 extra inches of aluminum or steel (depending on the wheel) weighs less than 3 extra inches of rubber? You're on crack. Everyone on this forum that has gone from 20s to 17s with the same size tires overall (35x12.5R20 to 35x12.5R17) and all of them have seen MPG gains off of that alone. So idk where your getting data from but unless your 20s are made out of super lightweight metal what youre stating is impossible

 

My truck is 2wd and 3.92 gears ratio, the tires i use are goodyear wrangler AT 265/70R-20. I hand calculated my mpg from time to time. Last year the highest I ever see was 13.75 mpg and the lowest 10.2 mpg. The last mpg was 11.6 mpg last week. I drive 40% city and 60% hwy so according the EPA I should be getting 15 mpg average but I ain't seeing that number at all. I thinking of putting nitrogen on my tires and see if that helps

 

My 2002 Quad Cab 4.7L Ram in full trim weighed 5125lbs with me in it on a certified NHRA scale at the track. The only thing NOT installed was the spare tire... Everything else was as it was delivered from the factory.

With that said there are MANY things that can and will effect your fuel economy. Its such a huge variable that it would be difficult to nail down your issue over the forums.

I would look at a couple things... many of them have already been mentioned.

1) TUNE UP! - Oil Change, Spark plugs, Coolant, Transmission fluid, Tire Pressure, Gear lube, ... Fill it up with GOOD 93 octane fuel every now and then!
2) Fuel Injector & throttle body cleaning - PROFESSIONALLY... They have a system that plugs into your fuel rail... Its worth it if you have never done this.
3) A clogged CAT can cause MPG issues - Check for any soft codes.
4) Reset Fuel Adaptives -
5) Run it WOT every now and then! This cleans up built up carbon deposits... Engines are built to rev!
-Questions.
What are the list of mods that you currently have?
What type of exhaust are you running? If your running true duals or even a cat back dual... thats part of your problem.
Are you running a throttle body spacer? If so thats part of your problem.
Are you running a 180 degree T-stat? If so thats part of your problem.

Nitrogen will do NOTHING for your fuel economy... All it will do is remain stable between climate changes from cool to warm and warm to cool... this would keep your tire pressure more stable. Its a waste of money.

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