incharlest

My situation is different than the other posts regarding misfire and hesitation. My es300 runs perfect when cold but once it reaches normal temperature it will begin to hesitatie once I step on the gas (soft or hard) from a dead stop. Seems to go away by about 30MPH
I have used scanners, fuel pressure gauges, and a vacuum gauge and have some information that might be useful. My fuel pressure is 54 (spec is 44-50). I have driven around with the gauge hooked up and this number stays the same even during hesitation, When I turn the car off the the pressure goes to to 50 and stays there for at least 10 minutes. Do you think I should just go ahead and buy a new fuel pressure regulator?
Also,I have driven around with my code scanner hooked up to the car and when the hesitation starts each of the short term fuel trim values go from -20 to +20. When one is high though the other seems to be low. They really bounce all over the place.
I have 3 O2 sensors and the code scanner provides the following values:
O2S12 (V) .745 (I think this gets closer to zero though when hesitation is occuring)
O2S11 (V) 3.303
O2S21 (V) 3.303
Shouldn't the O2 sensor readings all be about the same?
I'm new to using a code scanner for troubleshooting so any advice on what else to look for please pass along.
By the way, the MAF has been cleaned, same with throttle body, fuel filter is new, air filter is new, plugs look fine, all coils packs are within 2 years old.
One odd piece of information. I pulled the plastic cap off the fuel damper and the tiny screw has just sitting in the cap. I reinstalled screw but no help
If I took it to Toyota/Lexus would they be able to hook up a real fancy code scanner and be able to tell me what is wrong? I don't mind paying $100 or so to have them diagnose things if need be.
Thanks for any input.

hzt30

O2S12 (V) This is a regular O2 sensor after the converter. This should change(.1 to .9 volts) but not as much as a regular upstream O2 sensor. It will be different than the other 2 sensors.

O2S11 (V) 3.303 and O2S21 (V) 3.303 are A/F ratio sensors and are different than regular O2 sensors. These sensors should read the same or close to the same. The only way to check these sensors is with a scan tool. You can introduce propane to the intake and watch the sensors change value. They should change slightly above and below 3 volts.

What does fuel trim look like at idle and at 2500 rpms? If fuel trim is high positive at idle and gets better with higher rpms then check for a vacuum leak.