Cat power problems

I have a 96 e model cat that I need help with. I bought this engine for a core about 6 months ago and had a very reputable guy do the overhaul on it and it runs great, most of the time. Sometimes, very randomly, no rhyme or reason it will start running really rough between 900 and 1200 rpms and blow out clouds of white smoke while starting off from a stop. It may do it a couple times in one day and then not do it again for a whole week. The other problem is that when starting off from a stop I can easily push 42 pounds of boost and it just up and goes like nothing but as soon as I reach my desired speed which is normally right around 70 I can only push 33 pounds of boost anymore and it feels like a dog compared to when starting off from a stop. I’d like to get it fixed.

 

It’s a 1LW and yes it has been modified.

 

Yes he put in new injectors but like he said. Even new ones can be faulty. I’ll check the lines again but you’d think I have a fuel leak with cracks or loose fittings?

 

Yeah that to. He did do a cutout test a while ago when I had time to stop in one day but that didn’t bring anything up