Following my recent first oil change, I complained that my gas mileage had dropped (by about 10 percent), and no amount of careful driving would bring it back up.

Well, today I found the problem, and it had nothing to do with the oil change. In just three months, my tire pressures had dropped from 40+ PSI to just 28 PSI. I've never experienced such a quick drop in pressures in any car.

This is a heads-up for you to check your pressures much more frequently than you might expect.

The good news: with my tires at "healthy" pressures again, the increased fuel efficiency is immediately obvious. Formerly traveled routes are now giving me the same excellent MPG that they did before.

Maybe I'll see a mileage boost, as well, due to the new synthetic oil?

Note: my tire sensor warning light NEVER showed low pressures. When I reviewed the procedure carefully (page 168, in the manual), I noticed that you must leave the "Power" on for several minutes after resetting your tire pressures. Make sure you follow the procedure exactly. A final re-reminder to newbies: you MUST reset your tire sensor any time you change your baseline tire pressures, or the sensor will not work properly.

Tomorrow I'll be driving several hundred miles, and will confirm the gas mileage figures. Go check your tire pressures!

 

Steven: The serviceman my have reduced the tire pressure because most sedans use 27 or 28 psi.

 

Good point, David. I'll bet that's what happened, and it would explain the sudden nature of my gas mileage drop.

 

ya the manual also says the MAXIMUM pressure should not exceed 35 PSI where the maximum speeds are 160 KMPH or lower depending on your countries driving laws.

 

When I took mine in for service (both times) they set the pressures at the 32 psig listed on the door post. I run at about 36 psig.

 

I was wondering what people run at. I have mine at 33PSI with the Bridgestone.

 

The TCH door sticker says that the tire pressure should be set at 32psi. Since the standard Toyota service include tire check, that means the service techinican definitely reset the pressure to what it's "supposed" to be. Even when I've told service techs not to check my tire pressure, I've found it adjusted.

 

I got the nifty michelins!!!

 

I run 42 psi on the front and 40 psi on the rear. Tire wear has been very even so far (5,200 miles). I also have the Bridgestone tires

At my 5K service the tech reset my pressures to 35psi, my request to leave them at 42/40 not withstanding

 

Anyone who might be interested in topics about over-inflating tire pressures (or any topic, for that matter), first try doing a keyword search in the forums. There's a good chance that your topic may have already been discussed, and re-discussed. So much good information and documentation lies dormant in the annals of greenhybrid.com.