2000 ford f150 v8 engine and I pulled these codes of before it died.R 51Ee 02DT cf4fWhat is this?

Question

I drove the truck this morning and it drove fine for about 10 minutes and then it just died and would not start again I came back later whenever I got off of work and try to start again and it did until I got it all the way to the house and when I turned it off and then turn it back on to check the code it died again and these with a code that pulled before it died can you tell me what these are?
R 51
Ee 02
DT cf4f