My uncle has a 98 6.5 with 85,000 miles had a new pump put on it by gm @50,000 miles the problem is that when it is cold I won't sart worth a crap even if you cycle the glow plug twice still won't start easy but when it is warm it will start just fine warm as in when you get it started and shut it off . I checked the glow plugs only one was burnt out and they are working i even checked the lift pump it's working fine to What gives any help would be appreciated Turbo6600

Do you know what rating the glowplugs are? (9g, 11g, 60g?) If only one was burnt out, I'd have to guess they are 11s, so thats probably not your problem. Shouldn't be due for injectors yet, but you might have them checked out. Did the problem start when they changed the pump? If so, check and adjust TDC Offset if necessary.