Air Conditioner problems of the 2011 Ford F-150

On February 13, 2014, my Ford 2011 F-150 ecoboost began to show signs of limited throttle response coupled with a drastic reduction in power output and moderate to severe engine vibration. These symptoms occurred and were most severe under heavy engine load, while traveling uphill, high outside air temperature and with the air conditioner on. General locations: mojave high desert (joshua tree, CA) and the greater palm springs, CA area. Weather conditions were generally dry with low humidity. On February 15, 2014 the symptoms described above were so violent that the check engine came on (flashing) and I pulled off the road for my own safety. I shut off the engine, allowed it to rest¿� and then turned the engine back on. The symptoms did not disappear completely, but they were reduced and the check engine light was no longer illuminated. On February 20, 2014 I brought my truck to yucca valley Ford to have the problem diagnosed. Mileage at the time of the service was 68,382 miles. A diagnosis was performed and it was determined that the engine was misfiring on the number 1 cylinder due to worn spark plugs. All 6 spark plugs were replaced and the symptoms disappeared. The truck ran fine until approximately June, 2014. The symptoms slowly began to reoccur and by early August, had fully returned. On August 8, 2014, while traveling at freeway speeds, up a steep grade, with external air temperatures in the low 100 degrees, low humidity, and the air conditioner on, the truck nearly lost all power, began to misfire and vibrate violently, and the check engine light began to flash intermittently. Upon reaching the top of the grade and the load on the engine reduced, the symptoms were reduced. The truck was again brought to the yucca yalley Ford service center on Saturday August 9, 2014 where it is currently awaiting diagnosis.