Have a 2004 Tahoe. Random misfire code. Where to start to clear the problem?

check for vaccum leak or leaks.sometimes when vaccum hose split,dry rotted,or came loose,the computer will throw up false codes,i had one vaccum leak on pcv valve hose and it thru 9 codes,replaced vaccum hose,cleared codes and only cost $1.00,hope this helps.

Perhaps a professional scanner with live and freeze frame data will help... Just maybe..

remove your distributor cap and distributor check for rust, water may have gotten inside causing your misfire, I just went through the same thing on my Tahoe.