Nissan Repair: 2002 altima 3.5 P0300, crank angle sensor, cat back exhaust

Question
I recently install obx headers and a magnaflow cat-back exhaust system, and i going to install AEM CAI. i was in the process of installing when i notice that the air flow densor adaptor wasnt with the kit. so i put back the stock intake. now my car has no power, and im scanning P0300 and P0057. i need some advice, please help. thank you

Answer
Ryan,

P0300 is a random misfire.  Check to see if the crank angle sensor is good and if not replace the coils.  The P0057 is the heater wire or relay that heats the oxygen sensor.  So, check to see that a wire was not damaged when the headers and exhaust were installed.