2011 LEXUS GX460 Power Train Problems

THROTTLE ACTUATOR VALVE STUCK OPEN, REPAIRED 3 DIFFERENT TIMES & NOW SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE IS STUCK OPEN BANK 1 CAR STALLS OUT & GOES INTO LIMP MODE. CHECK ENGINE LIGHT, 4LO, TRAC LIGHT- VEHICLE IS UNSAFE TO DRIVE. CODES P2440 & P2442 THIS IS A FAULTY PART ON TOYOTA TUNDRA & SEQOUIA.

1.WHEN GOING DOWN HILLS IN D GEAR, UPON REACHING 55-60 MPH, WHEN THE BRAKE IS TAPPED TO SLOW DOWN THE TRANSMISSION SUDDENLY SHIFTS DOWN FROM 6TH GEAR TO 4TH GEAR AND THE RPM SPIKES TO AROUND 4,000 RPMS. 2.THIS PROBLEM WAS REPORTED TO THE SERVICE DEPARTMENT OF BERLIN CITY AUTO GROUP, IN PORTLAND, MAINE, ON OCTOBER 13, 2013. THE CAR WAS DRIVEN BY A MECHANIC ON A FLAT ROAD (EVEN THOUGH TOLD THAT ANY TEST NEEDED TO BE ON A HILL WHERE SPEEDS OF 55-60 MPH COULD BE REACHED); THE REPORT WAS THAT EVERYTHING WAS FINE; NO PROBLEM. 3.ON OCTOBER 17, 2013 A LEXUS AREA REPRESENTATIVE DROVE THE CAR WITH A COMPUTER CONNECTED TO IT AND THE SAME PROBLEM AS NOTED IN NUMBER 1 WAS OBSERVED. THE THROTTLE BODY WAS CLEANED AND REPLACED ON TWO SUBSEQUENT VISITS; PROBLEM NOT SOLVED. ANOTHER LEXUS GX 460 WAS BROUGHT TO THE AREA AND...