My car is misfiring horribly sometimes, along with what sounds like piston knock coming from the right side of the block. Im getting the codes, p0010 (intake cam positioning solenoid bank 1)(symptom 00), p0011 intake cam performance bank 1(symptom 00), and p0420 catalyst efficientcy low (symptom 00). I know its not the sensor, or could it? Some info about the car: Awhile ago my flex piece broke and eventually I was driving without an exhaust system for 2 or so months. Then I fixed it and replaced the cat with an eaton downpipe. Its a 2009 LT. Any suggestions anyone?