Has anyone calculated what the PSI change brings in terms of extra MPG? For example 32 increase to 34 will boost MPG by 3. Going from 34 to 38, etc.

 

I'm not sure about how easy such a relationship would be to establish, as there are far more uncontrolled variables present than just tire pressure. Things like traffic patterns, subtle temp changes, wind direction, and even the chemical composition of the fuel going in would all be 'wild cards'. Other variables include average speed - tire rolling resistance is less of a contributor to fuel consumption at high speeds (air drag) than at low speeds. For most normal driving, the direct tire inflation related difference is likely < 5% for the relatively minor changes in pressure.

That said, Toyota does have a 'high-speed' pressure recommendation (for sustained operation >100 MPH) to increase pressure by 3 PSI (page 404 of the 2008 manual). The primary focus is to reduce flex and risk of tire failure, but a secondary result is lower rolling resistance. With other cars I've had in the past, the 'high-speed' spec would not noticeably compromise any operational aspect, and that seems to be the case with the TCH as well. On 'crunchy' roads, I'd hesitate to 'go radical' with 40+ pressures, mainly due to the fact that they'd make worse the car's tendency to develop rattles. If the roads were ultra-smooth in my primary drive area, maybe - but here, the pavement warts and some of Toyota's trim attachment engineering solutions make me hesitate...

Kinda makes you wonder about the guys with 30-profile tires complaining about rattles...

 

I have found that most Toyota dealerships still have 5W-20 or 5W-30 in their bulk tank. And 0W-20 in quarts (Toyota genuine, ENEOS, or Mobil 1)

So, do not assume they put in the right oil. Unless, you specifically state that you want 0W-20, they most likely put in the bulk oil.
Frankly, It is cheaper and easier to do so.

Other choice is to bring your own 0W-20 in and have them do the oil change for $10-15 for labor.

Here is a list of all API approved 0W-20.
http://eolcs.api.org/FindBrandByVisc...iscosity=0W-20