After dealing with worsening engine knock on startup and increasing coolant consumption for a couple of years, I had my 2012 Prius engine rebuilt by a recommended independent shop. It's running fine now. I've had it back for about a month, and the mileage is now just under 40 mpg. It average around 48 mpg before the rebuild, so that's a 20% drop in fuel efficiency! I did have two tires replaced (old were Continental True Contact, new are General Altimax RT43), but I think that could only account for a few percentage points. Any suggestions about what to check? Thanks, Luke
We ask people to identify the region they live in because this drop in MPG is largely weather related. When temps are up near 80 degrees Fahrenheit and you have your tire pressure boosted up to max or better is even higher your MPG will return to normal. Assuming you're in the northern part of the northern hemisphere, it's currently too cold to get good MPG unless you're further to the south.