2005 GMC Yukon Xl 1500

HELLO AROUND THE BEGINNING OF JUNE OF 2011 I WAS DRIVING MY 2005 GMC YUKON XL WHEN SUDDENLY I RECEIVED AN ERROR MESSAGE ON MY DASH BOARD STATING "REDUCE ENGINE POWER" AUTOMATICALLY MY SPEED WENT DOWN. I PULLED OVER TO THE SIDE AND DID A DIAGNOSTIC CHECK WITH ONSTAR, THEY INFORMED ME THAT THE ENGINE SUDDENLY WAS REDUCING SPEED AND THE BEST THING TO DO WAS TAKE IT IN TO GET CHECKED AT. ON MONDAY, JUNE 6TH I TOOK IT IN TO BOB BROWN DEALER IN MERLE HAY IN DES MOINES, IA, I SPOKE TO BOB LUNDY AND INFORMED HIM OF THE PROBLEM I WAS HAVING, HE INFORMED ME THEY HAD TO DO SOME DIAGNOSTIC CHECK AGAIN, I LEFT MY VEHICLE THERE AND GOT A RIDE TO WORK FROM THEM. IN THE PM I RECEIVED A PHONE CALL FROM BOB STATING THAT ALL IT WAS JUST A SENSOR SO THEY WOULD HAVE TO REPLACE IT I INFORMED HIM THAT WAS FINE AS LONG AS EVERYTHING WOULD BE FIXED. THEY CHARGED ME $457.02, ABOUT A WEEK LATER THE ENGINE LIGHT CAME BACK ON AND REDUCE ENGINE POWER KICKED IN AGAIN, I CALLED BOB LUNDY AT THE GMC DEALER AND HE STATED THAT THE SENSOR MIGHT HAVE GONE BAD AGAIN. I WAITED ABOUT 2 WEEKS AND TOOK IT IN AGAIN AND THIS TIME THEY CANNOT FIGURE OUT WHAT IS GOING ON WITH MY TRUCK, I EVEN LEFT IT THERE OVERNIGHT AND ALL THEY CAN TELL ME IS THAT THEY CANNOT FIGURE THE PROBLEM OUT. I AM OUT $452 DOLLARS AND THE REDUCE ENGINE POWER ACTS UP ALMOST EVERYDAY! I HAVE TO KEEP PULLING OVER IN THE INTERSTATE, STREET, OR ANYWHERE I AM AT IN ORDER TO TURN MY VEHICLE OFF FOR 5 MINUTES AND START IT OVER FOR THAT ERROR MESSAGE TO GO AWAY AND FOR ME TO BE ABLE TO DRIVE MY VEHICLE APPROPRIATELY, OTHERWISE THE ENGINE POWER IS NOT WORKING AND I CAN ONLY DRIVE IT UP TO 20 MPH. SOMETIMES EVEN WHEN I RESTART MY VEHICLE THE MESSAGE IS STILL THERE AND I HAVE TO WAIT AND LOOSE MORE TIME. THIS IS AFFECTING MY EVERYDAY LIFE, I HAVE BEEN LATE TO MEETINGS, WORK, TO PICK UP MY DAUGHTER. I WANT THIS FIXED PLEASE! BOB BROWN DEALER STATED THEY DON'T KNOW WHAT THE PROBLEM IS WITH MY VEHICLE, I THINK THEY JUST DON'T KNOW HOW TO FIX IT!!! *TR