This is my first shot at a forum so bare with me. My truck started running really rough,so I pulled some codes, one time I got 31,41,12. another time after changing out my o2s I got 12,23,42,31.The crazy thing is it will run terrible and while I do nothing it clears up.Other times I drive down the road fine and out of nowhere it starts running really bad,it may clear up in minutes or a day or two? While giving gas on the road its ok then I back off it jerks and bucks like crazy! When I come to a stop I have to drive with two feet to stay running,and it bucks like crazy! Yesterday I was in my driveway idling crazy bad,as I looked at it not touching it,it cleared up. after it cleared up I pulled my codes and got only 12.Its forever changing and so do my codes.When it does clear up the idle is too low,and if I start it cold and it wants to run good,it does but it never idles up to get warm like it should.Its like jeckle and hyde I never know what it will do? Please help!!! I dont get it??