I have a 1993 chevy 3500 rollback just purchased, it has 170000 miles. It starts ok when cold but intermitantly it is very hard to start after sitting for a few min. when started cold or hot it puffs blue smoke for about a minute. also when driving it has low power. I downshift on very small inclines even when unloaded. I am a gasoline mech. but never worked on diesels much. i assume blue smoke is related to valve seals or guides but not sure of other problems. Any help would be great.  Thanks.  

I would start by running a cylinder leak down test. more than likely sounds like valve seals are going out. may want to check the glow plugs. have had trouble with powerstrokes on hard starting cause of bad plugs. jw  

I also have a 1993 6.5 thath had the same problem. We took it to a diesel shop and he said it was the injection pump and it cost about $1000 and that fixed it. also for hard starting you might check glow plugs.  

I also have a 1993 6.5 that had the same problem. We took it to a diesel shop and he said it was the injection pump and it cost about $1000 and that fixed it. also for hard starting you might check glow plugs.