97 7.3 wont start
 

I was driving my 7.3 down the road when all of a sudden it died like I had turned the key off and wouldnt start back up. I towed it to my houseand trued to start it on starting fluid. it would start for a second then die.Thenn hooked it up to a code reader where it pulled codes p0603 p0344 and p0340 two of which are cps codes. I replaced the cps and it still wont start. It doesnt pull any more codes. Any ideas of what else it could be?:argh:

Never ever ever use starting fluid! Did you check the oil?