I'm sorry but I just dont buy that cleaning off your throttle body butterfly plates gained you 4mpg...you could polish them to a mirror finish and that wont even gain you 1mpg.... hell you could open the holes up to 50mm and polish the whole damn thing like I did and it still wont do much for gas mileage...
Maybe your air cleaner was plugged and now its replaced?

 

i average 15.3mpg city/40 miles of highway a day at 70mph. But its flat as a pancake here and at sea level.

 

If you walk into Advanced auto parts or autozone you walk through and there are aisles and aisles of products that say get better mpg I was wondering what is crap and what actually works. I know the basics easy on the gas and use cruise control. Sorry for the confusion.

 

Nope same air cleaner and everything. I'm not the person that goes by what the can says, I go by what my mileage divided by the gallons it takes to fill it.

 

None of it really. Most of it is snake oil, and gimmicks. There is no magic bullet to make your truck get good gas mileage. They are what they are, heavy bricks, that suck gas.

 

There are ways to get better mileage. As stated before, the general maintainence and fixing any issues, as well as gearing, will benefit you the most. But there are others, although not practical or cost effective, that can net you even more MPG. Cylinder matching, porting, blueprinting, aerodynamic designs can improve mileage significantly. Although I've never been able to technically "prove" this, it has been done. HankL was or still is a member here who was brilliant on the subject. There are some threads/posts he explained such techniques. Apparently, 360s and 318s should be able to achieve 20 mpg from what I've researched, with perfect conditions. Dodge allowed a 25% tolerance in the designing of our Magnums, so you can imagine if you fixed that 25% how much more efficient our engines would be...

 

Consider what you are starting with though..... big, heavy, aerodynamic as a brick.... There is only so much you are going to be able to do, within a reasonable budget, and even then, you will only get a point or two better fuel economy for your money. (this is more toward "extraordinary" measures, not maintenance items.) Now, if you are doing some work anyway...... say, rebuilding the engine, doing things to increase it's efficiency is not a bad idea.

 

ok well then something else changed like your gas.... because there is no logical benefit to what you did to cause a 4mpg increase... maybe your map sensor was pluged or something and you got cleaner in there inadvertantly... or you spilled cleaner down into the keg and it burned some of the soot off one or two of your plugs that are fouled from a blown plenum or pvc/ blowby? (seafoam works better for this btw)
just saying look at it from a logical standpoint cleaning off any residue off your butterfly plates should be just as effective as waxing your grill...

 

and when you lift them it creates more resistance= less mpg... wide or agressive tires can cost up to 4mpg more.... and having the gearing that way out of whack for tires size costs even more mpg in many cases... this is why the reported mpgs vary so much here on this forum...rip out things such as the cat and you throw off flow and 02 sensor reading which can also effect it.. bigger throttlebody can mean more air if other mods support it = more fuel used most of the people who do all the wrong things for looks are ironically usually the first ones complaining about the gas mileage... its an endless cycle.

I have a lift and agressive tires and such but I understand the limitations of what I've got and dont expect miracles...

 

Ya my truck has the stock 16 inch painted aluminum rims. So the tires shouldn't affect it. I still have the window sticker from when my truck was bought in 1997 and it says something like 13 city and 17 highway. Does putting nitrogen in the tires instead of air help out any?