I have a 2007 Ram 1500 with 110K miles. I had a P0306 code and eventually replaced all the spark plugs and #6 injector (after determining the coil was OK). The code went away for all of one test drive. I took it to the shop and found only 47 PSI compression in #6 cylinder. Going further, the mechanic found a hole in the #6 exhaust valve. After $2400 in repairs, the P0306 code eventually returned. The misfire is obvious when accelerating in overdrive. Turning off overdrive helps a little. At someone's suggestion, I replaced the air filter and cleaned the IAT sensor with a Q-tip, and it stopped misfiring, but only until the need for acceleration. On a local Dodge dealer website, I searched for manufacturer's recalls and found there is one for "EGR Diagnostic Monitor". Could this be the cause of a consistent P0306 code?