Gas Mileage with an Oil Change

Hey,
I have a 2000 tacoma with a little over 125,000 miles on it. I have the oil changed every 3,000 miles with full synthetic oil. I have noticed that towards the time the the oil needs to be changed i get lower gas mileage (about 15 mpg) than when i first change it (about 17 mpg). Wondering why this would happen to my truck.

 

Filthy oil probably has more friction I would suppose.

 

There is some other variable you are missing.

Unless you have a competitive vehicle of some type with a very heavy duty cycle, full synthetic oil should last at least 10-12k. Proven by independent lab studies, and you can have your own oil tested to validate. You are both wasting money and resources.

And the worst contaminated 3k oil (of any type) would never introduce enough friction to drop 2 MPG.

 

Dino oil every 3k miles is throwing away a lot of good oil. Synthetic every 3k is throwing away a lot of good money. If your oil is so crudded up it's dropping your mpg 2mpg you should be seeing liquid metal pouring out of the oil pan.

Odds are it's the driving style that's affecting your mileage. And before you say it, no you don't always drive the same

 

Change mine every 4000 does the same thing. Mpg goes to shit when it's around 3500 to 4000. Dnt care what your saying does it every time!!! Also where I live dealer calls for oil change every 5000. Now what???