2007 Highlander Hybred 4WDi

My wife and I purchased this Vehicle new in October 2006. We have 60K miles on it and have maintained an average of 27MPG for at least 50Kmiles. We had a 50K service completed in the spring of 09 by a Toyota dealership and it was badly performed. They did not refill the radiator with coolant and all the red lights came on just 2 miles down the road. My wife immediately drove it back. The dealership issued a loaner car and had it ready the next business day. I noticed that I could hear water or bubbles in the heater core after it was supposed to have been refilled. There were no red lights but I took it in to another dealership here in Phoenix area and they hooked up the computer and noted that it had been running at 215F instead of thermostat temp of 195F. They topped it up again and resolved the water running noise in the heater core. This car has only been serviced by Toyota. Only 3 dealerships in the Phoenix area have touched the car. We have noticed a steady decline in Mileage since the bad service last year and it has hit an all time low of 20MPG. This is 30% less than what we had been averaging over 50K with many different driving conditions. We averaged 24MPG running at 75-85mph all the way from Arizona to Washington State 2 years ago. We just took it into the dealership that sold us the car and they can’t find anything wrong. We put some 44K in it with no real improvement. It seems like the whole transmission shift profile has changed. It rarely kicks on the motors like it used to and the motor stays reved after accelerating to pass even though the gas pedal is backed completely off. In the past the CVT always shifted down to allow the engine to drop RPM. I am wondering if the hotter running temp caused some damage to the CVT? The only things I would think that could cause this kind if significant mileage drop is either the Hybred Battery or problems with CVT. Our mileage has always been calculated by setting one of the trip meters to 0 and filling the tank up when it gets low. I always wait for the pump overflow sensor to kick off and never add any more at this point. No topping off. The tires were changed from original Good Year to same Size and low rolling resistance tires from Yokohama. We almost always gas up at Costco and my wife usually purchases the premium blend.

Too hard to read.