2001 Jeep cherokee throwing codes
 

Hey,
Ok so heres the deal. My GF has a 2001 jeep cherokee. lately it has decided to start throwing codes. mainly the P0300(random misfire)and also the codes that relate to misfires in the specified cylinders(P0302,P0303,P0306) I have tried the obvious being changing the plugs and the coil. now im looking where to go from here. After replacing the coil and plugsI cleared the codes and within 3 days the P0300(random misfire) was back. the other symptom that the jeep has is its horrable when cold starting(Being when the engine is cold) once we take the jeep for a drive shut it down it starts like a dream if we restart immediatley. But back to my main concern. anyone know what is causing this code? I tryed the jeep forum and got nowhere. Thanks guys any comments would be appreciated(But not ones bashing jeeps i bash it enough and she wont sell the thing)