when I had a 8,500 lb boat/trailer it got 7-8MPG going up from sea level to +6.5K feet (Lake Tahoe). Get 15.4 MPG often enough to claim, but not often enough to count. With LT265/75R16 E's on 16x10 Alcoa's, so the "real" diff ratio is around 3.9.ĭepends on what time of year and the various gas blends available. Oh and here are a couple of pics of my truck: that was the only time that happened.ĭoes warmer weather alter performance and mileage? lately it's been in the 90's here and i average 7-8 mpg mostly city. one time i drove to florida(from IL) in the middle of winter and i calculated 14mpg. It seems like my mileage and performance go down with the hotter weather. the truck does have a 3" bodylift along with the 265/75/16 tires, and yes i have a bed cover. The truck is almost always empty, never haul anything. i dont really notice much difference by using better gas. I usually use 87 octane and i purchase gas from all places. The truck ran alright before i did all this, but it had a little coolant leak, some piston slap, and took a few seconds with the starter to get it started. actually the only thing i never changed was the MAF sensor.
the truck has 190k miles on it, BUT about 30k miles ago(when i bought it) i put in a completely new(not rebuilt) motor with all new sensors, injectors, intake manifold, throttlebody, distributor, coil, o2 sensors, radiator, banks cat back exhaust. it has a 454 vortec and 4l80e trans and 4:10 gears. it's a 96 gmc 3/4 ton 4x4 extd cab short bed. When the solenoid is hot it won't work till the whole works cools down. You must shield the starter if you go this way though, as headers on a big block will cause starting problems.
2003 8.1 VORTEC MPG FREE
Headers can improve mileage, along with a free flowing exhaust. You want a setup that flows better than 5000CFM.Ī bed cover can improve mileage by reducing drag. Make sure to get flow though, because you can overheat easily if you don't have the right fans. And, it'll make the AC work better in the summer and help the truck warm up faster in the winter. On a SBC 350, 2000 to 2200 is the ideal cruise speed, and gears to put cruise in this RPM bad is best.Įlectric fans can add 2MPG or better to your truck. Don't get tooo wild though, because if you go too far it'll make the engine work too hard. What rear gears do you gave? Getting a larger (lower numerically) gearset can improve mileage. Changing them can gain up to 5MPG, but only if you are now getting 5MPG less than when new.Ī computer reprogram aimed for mileage can make it better. How old are the O2 sensors? They can get lazy after 50K - 100K miles.
If it's been more than a few years, this needs to be done. Last tuneup? New plugs, wires, cap and rotor, and a new coil, will make sure enough spark is there to burn all the gas. Change the oil immediately after using this as it will contaminate the oil. After the 15 minute wait period your truck will smoke like it has a blown head gasket for about 15 minutes, the smoke smells like bad gunpowder and clings. When you follow the directions, make sure to do it away from the house. It goes in the throttle body slowly, then dump the last 1/3 can in till the engine stalls. You can get a quart of GM Top Engine Cleaner. Mileage should decrease for that tank, then increase to more than the decrease on the following tank.
2003 8.1 VORTEC MPG FULL
You can add a quart of Marvel Mystery Oil to a full tank of gas. How is the truck used? If it is a work truck that carries a lot of gear, weight reduces mileage. And, at the 10-15MPG range gaining 1MPG is the same as saving 12 cents per gallon, so don't be afraid to spend 2-3 cents a gallon more for the same octane, if you get better mileage. For example, my 96 Tahoe gets 2MPG better off Shell than anything else in my area, but the wife's 89 GMC Jimmy S15 gets the same regardless of brand. Yes, it all comes from the same place, but the different brands have different additive packages. What kind of gas do you use? Different vehicles burn different brands with different results. Let's do this cheapest to most expensive: My 96 3/4 extd cab 4x4 with 265/75/16 tires is getting 7 mpg with the heat and ac going. George wrote:what kind of gas mileage is everyone getting? with a vortec 454?