hey guys,

i have about 5500 miles on my truck now. i also have some mods (see sig). i have been getting pretty crappy gas mileage the whole time i have owned her. i get about 12-13 mpg. i dunno, are all the v6 guys b.s.'ing me or am i the only guy not getting 17 mpg?? i have been waiting to say something because i have heard stories about the engine breaking in and whatnot. if this is normal and nothing is wrong then that is fine...i can deal with that. i am just concerned that my poor mileage is because of some kind of malfunction. am i just paraniod? please tell me i am thanks for the info. by the way i know this is not exactly the right forum...i just want mikes take on the situation as well.

 

Hi LBC150,

At 5500 miles, you're just now getting that motor loosened up and making it's best power & mileage, etc. So I wouldn't worry too much about what you've gotten in the past, but what you get from here on out.

This can be an issue of fuel quality, there is enough difference in energy content to show a difference of a couple of mpg in these heavy vehicles. This goes doubly so when you use the Superchip, as if the premium gas doesn't have a good high energy content, even though the octane is there, you won't see the mpg. Add that in with some spirited driving every now and then checking out the performance of a few modifications, and you can easily see why it could be that you might be getting a few less mpg than what other 4.2 V-6 owners get.

Are you doing your mpg calculations precisely? Filling up at the same station and in the same method each time, letting it stop at the first "click" of the pump, no topping off, etc., and then dividing the exact # of miles you drove by the exact number of gallons it took to refill the tank? You'd be surprised how many people don't really calculate their mileage precisely or consistently, etc., and that too, can be one of the pieces to this mpg "puzzle," so to speak. I know that sounds so basic as to perhaps be silly to mention, but you never know........

The first thing to do is to make sure you are using the best premium gasoline available to you, and the way to determine that (from an energy content & mpg aspect) is to use 3-5 tanks of each different brand/source, and compare mileage. At the end of your comparisons, the fuel that provided the highest mpg under the same basic driving conditions is the fuel with the highest energy content, generally speaking. It's a bit tedious procedure that most people won't make time for in their busy lives, quite naturally, but that is the way to identify which fuel in your area is going to deliver the best mpg results.

Routine maintenance, such as fuel filters & making sure the MAF is clean (which shouldn't be an issue with 5000 miles, but on rare occasions can be), how you drive it and the fuel you feed it are obvious issues. You should also have your wheel alignment checked, as sometimes they can be significantly out of whack from the factory alignment can certainly make a difference in mpg. Also make sure your tires are properly inflated, etc., you know, all the basics.

This probably isn't telling you much (if anything) that you don't already know, but sometimes it just helps to have someone remind us of the basics.

There are other changes you can make to bring up mpg further, such as electric fans, for example, and you may already be thinking along those lines as well, since you already have the ASP crank underdrive pulley for the V-6. Denso Iridium plugs can also help a little bit, it all adds up.

I hope this simple info helps a little bit, & good luck!