Hmm, I have a 92 pick-up with a 6.5td that came with it new. This guy says the trucks didn't have a 6.5 untill 93. Makes me doubt most of his info. The ip's weren't failing it was the pmd.
No diesel BURB from 92-93 AFAIK. The 92-93 trucks got by with an emissions loophole basically, this is why the 94 trucks, and everything from 95+ has teh DS4 pump in it. Also the DS4 pumped cleaned the emissions up enough to get em squeeked by for SUV's and 1500 trucks.