Oil vs MPG

Gonna keep this short and simple. Before my last oil change, I always used Pennzoil conventional or Kendall Synthetic blend depending on price/if I had a shop do the change. With my lift and tires, I consistently got 15-16 mpg. Now, after my last oil change with Mobile1 Full Synthetic, my mpg's have significantly went up. My last 4 fill up's have been: 18.4, 20.1, 19.5, and my last one was 22.4! The first three were all city mpgs, but the last one was highway driving. Is this normal? I'm pretty damn excited.

 

Anything is possible and numbers don't lie. Besides, every vehicles reacts differently to modifications and changes.

 

I know changing old oil to new is good for mpg on a big fleet-wide average but that's way big improvement... did ya change oil weight? still, even that doesn't explain such a big change. There has to be something else you 'touched'. New air filter? Weather cooler so using A/C less? Driving style change? Hard to imagine oil alone accounting for that much improvement unless you went from 90 weight to 20 weight.

The only accurate way to measure mpg is record gas put in at fill up and divide it into the miles driven since last fillup. Do that over several fill ups (total gas used divided into total miles driven) and you get an accurate average mpg. Using the instrument cluster readout isn't that accurate (but very useful for instantaneously gauging gas use and adjusting driving habits accordingly.)

 

I used the same weight. I clean my K&N at every oil change. Weather has been around the same, maybe a little warmer. Same driving style except for that last fill up was all highway mileage. I use this app called "FuelLog" to monitor my MPG's. I enter my current odo reading, how many gallons, and the price after every fill up.

 

Sounds fishy. No new plugs?

 

Nope. i just remembered though that I put some LR UCA's on the same day I changed the oil. Would being in correct alignment help too?

 

Yes it would... tire scuff (from bad toe-in, for instance) is a gas-eater. I assume it was mis-aligned before the UCA install, when you also got an alignment? Was it significantly bad?

Don't know if it could account for that much but there's more here than just an oil change to be sure.

 

The only thing off was the camber. It was just eating the outsides of my tires.

 

Maybe a data entry error? I've done this many times with my Scanguage!
You will see as you enter more tank usages!

I always notice better MPG after a oil change but only lasts 1-2 tanks and about 2-4 mpg better.

 

bingo

 

Go back to Pennzoil and see if it goes back down.....

 

I went from the factory oil to Mobil 1 recently, no change in MPG.

 

x2, did the same thing and no reported change in MPGs.

 

there's the change!