How long does new engine need to adjust for fuel economy
 

I was wondering who bought a new vechile. How long does it take for the engine Get the right fuel economy. Does it take time for computer and sensor adjust the engine for breakin period . Let me here your response my new vechile seem not getting good milage yet.

Actually, most of the breaking in is in the tires. They have a higher rolling resistance when new. It will take a few thousand miles for them.

I got two new tyres last summer and they ruined my mpg. I had only just got the numbers back up when I had to replace one of them, and now I notice the difference again.
Four, brand new, P285/45R22 AS BW tyres must decimate mpg, until such time as they have the edges rubbed off. I would imagine almost 5,000 miles (going by my experience).
Tyres are at their best, mpg wise, just before you have to replace them!

The EPA doesn't allow more than 4000 miles worth of tire wear on tested cars.