Hello, I am hoping you guys can help me with some issues I've been having with my truck. I have been using the search function on this site but I am stuck. If this has been covered, I apologise.
For awhile I had been having issues with low boost. After checking the vacuum system I discovered a faulty solenoid. I replaced the part and the truck ran fine for a few months. Then things got a whole lot worse. No boost, no power, tons of smoke. The computer gave me the PO236 and high EGR codes. As a last ditch I cut off my Catalytic converter (couldn't get it apart otherwise due to rust) and ran around with just the down pipe (I know, I know I'll keep the windows open ), waiting on a new exhaust. The cat was packed. I cannot believe the truck even ran at all. What a difference in power. I can hear the turbo. I get boost and peak at about 12 pounds until the computer kills the boost at high RPM.
Now my issue is that about 1/3 of the time I give the truck throttle and the truck seems to fall on its face. It makes a little boost (1-3 pounds), it blows smoke, and doesn't want to rev. The boost and RPMs will often slowly go up. This is significantly more than typical turbo lag. This seems to occur in the mid rpm range. Also, the computer is giving the code for low EGR flow. I assume because there is no back pressure. Does that have anything to do with my power issues.

Thanks for help and wisdom