I'll go out on a limb here and say they checked the air filter. So, when they put it all back togeather, they either plugged back up something that's been disconnected(the reasoning for the poor mileage) or they plugged something back up that wasn't seated good before.

Yeah, it's a long shot and seems that something would have triggered a CEL, but, stranger things have happened.

And yes, Let us know if the gas mileage does increase after a tank or two.
Just remember it's winterblend fuels now, so the mileage could be down a little from the summerblends.

 

My wild guess is that they disconnected the MAF then plugged it back in securely. Been more than one not fully connected or broken wire.

 

Typing at the same time George.

 

It's been since January 9 and the mpg is MUCH better than before over the same routes, times, etc. Everything that has been said seems to make perfect sense and I guess stranger things have happened. As I mentioned earlier, the car only has 16k miles on it but it IS five years old. I bought it last June when it had only 10k miles on the clock and, very obviously, had only been driven on short trips to the grocery store by the previous owner.

 

Thanks lucky. Appreciate the info. I am thinking it is because of the different size tires I had installed. I think i remember the mileage difference about that time.

 

I once had an oil change done on a Toyota Pickup whith BG added to the oil. I was amazed at the increase in my gas mileage, it was about 5 MPG better for a couple oil changes after.