Sudden MPG Drop

Hi there.

I've suddenly gone from very reliable 22 mpg tank averages to 18 mpg tank averages. My last two tanks were 18 mpg average (17.81 and 17.90 to be specific). I don't have the economy calculation in yet on my third tank but just judging from the miles covered, it's not looking good.

My driving style hasn't changed as far as I'm aware.

I've checked:

-Tire Pressure
-Air Filter
-Put truck on jacks and made sure wheels rotated freely (No hanging brakes).

What else should I look into to make sure there isn't a problem with the truck that is causing the economy drop.

Thanks homies.

 

Try a different gas station.
Has your station recently started using an ethanol blend?
Some stations have been caught pushing more than 10% ethanol, and sometimes, E85 i mistakenly put into the normal tanks.

 

Arco gas maybe? I can see my gas drop faster from gassing up at different station. Well, that's what is seems like to me.

 

Thanks, didnt think of bad gas. Im going to burn off the last of this tank tonight and go to a different station than my regular one to fill back up.

 

The truck has 41k miles on it, would it be due for plugs and a fuel filter by any chance?

 

you shouldn't need plugs yet and I am pretty sure filter should be good too...I have 70k and just changed my plugs...didn't see much MPG gain. I had a similar drop in MPG to yours. It happened right around the time ethanol free gas became impossible to find here in SLC.....

 

OP has the four cylinder, that comes with iridium plugs from the factory good until ~100k-ish.

x2 on going back to your typical gas station. There's one two miles up the road, it's conveniently close -- but I don't ever fill up there. Big mileage drops. I'll drive the extra three miles to Meijer or the Speedway because it more than pays off. I know it's not their pump measuring either because it always shows up on the next fill wherever I go, not to mention almost immediately on the ultragauge.

The only service I'd think about myself at that mileage is the rear diff fluid, although mpg-wise you won't see much of a difference. It's not in the maintenance schedule (ever) but I plan to do it anyways every 30k. My '09 was really dark at 33k miles.