My 99 suburban,.......... i parked truck way back because i tried to do a KOKO and it had no resistor in. As soon as ecm saw 170 deg it would cough splutter couldn't find its timing, clouds of smoke. we had a scanner try to turn off the relearn but to no avail. I finally acquired another ecm, so i got the truck running, warmed it to only 150 or so, shut it down swapped ecm's. I did the 3X10 min key on relearn for the security system and she fired up nicely idled great,. left it running for about 20 mins or so all just perfect. I shut it down and after an hr i restarted it just fine. i tried again after 2 hrs more and no spark,.. rolls over and not even a kick,. so i verified a good fuel flow hot wired pump opened bleed etc,. glow plug relay clicks just fine,. i swapped pmd's,.. I am now thinking the pump has given up the ghost,.I have gotten a few 6.5's running over the years,.but this one seems to be a problem child,.