I have a 2004 fx4 f150 with 149,000 miles on it. recently I have noticed that when I'm at a stop light in idle my rpms rev up high and backfire. Then after the backfiring multiple times my truck shuts off and the check engine light comes on, but it starts right back up and the check engine light turns off. It doesn't do it all the time either does it randomly. It only happens when I'm at a complete stop but when i drive it works completely fine. I was wondering if anyone had any ideas to why it was happening

 

You should try pulling the code when that CEL comes on. Pick up a code scanner or something to check it out with