Yes check for DTC's. There may or may not be codes present. Having done this for many years now I with relate a few findings;
1) I have never seen the issue fixed with "parts"
2) I have had people claim to have spent as much as $9k chasing this only to be fixed with tuning
3) The tuning fix does not eliminate the need for fuel system upgrades (lift pump etc)
More reading:
http://www.kennedydiesel.com/docs/Du...20detected.htm