Poor Mileage --- 2013 Prius

try a throttle body and maf cleaning. and clean the egrcircuit.

see @NutzAboutBolts youtube diy videos

 

I have a 2015 Prius with only 41,500 miles. I can’t seem to get over 37 to 39 mpg combined City and highway. Tires replaced around 10,000 miles ago, we installed required rolling resistance tires (psi 35 front, 33 rear) Oil and filter changed regularly (3,000 to 5,000 miles). Engine air filter changed yearly. Any recommendations on how I can get it better?

 

What brand of tire? Their info may say RRtires, but not for a Prius.
That's what the info for my tires said. I gained about 4 mpg in the city.
But lost about 6mpg on the highway. 90+% of my driving is highway.
I dropped from 48 to 42mpg. HUGE for me. These might just get nail on the outer/inner
tread so they'll have to replace them with better tires.
It pays to get road hazzard insurance.

 

Michelin tires purchased at local Toyota dealer. We owned a 2010 prius prior to this that got much better mileage.

 

What specific Michelin tire?

 

Michelin Premier A/S 195/65R15

 

There have been reports here about those, they dropped mpg significantly. I think the sidewall says "Total Performance" instead of "Green X".

I really have little faith in either of those labels btw. I replaced our OEM Michelin PIlot hx MXM4 (with "Green X" badge), with Michelin Primacy MXM4 (also with "Green X" badge") and our mpg dropped significantly . Very gradually has climbed back up, still not back to pre-swap level though.

My take, you've got to take each tire as an unknown quantity; the manfucturer's claims have little merit.

 

Try this takes only 3 minutes. I’ve gained back 5-6 mpg simply by performing this reset. Also fuel system cleaners.

 

I've seen this posted a few times. Can someone explain the relation between the steering angle sensor and fuel economy? Thanks!

 

It seems to reset ECU and improves steering and braking.

 

but not mpg's?

 

Welp, found a portion of your issue right there. 35psi front and 33psi rear is not high enough to achieve the best mpg. I keep all 4 tires (Bridgestone Ecopia's) at 42psi year round. In the winter time (currently) I usually get 44-46mpg on average per tank. I also have my grill blocked 95% and when a chubby friend wants to go somewhere, I insist we take their vehicle so they dont mess up my mpg averages Kidding, kidding! (.... or am i?) hehe

 

Tire pressure can't affect MPGs that much. I live in a pothole-infested area and I only set my tires to 32 psi and I still average 47-48 mpg.

 

That guy doesn't seem to know what he's doing or why. Read an explanation here.

 

I set mine to 44psi and still average 67 mpg, ytpms

 

Good for you. Must live in a nice area. I can't even raise my psi to 33 or above otherwise it's too uncomfortable and I feel all the bumps. I have Michelin defenders.