My truck had the same issue with my mechanical wastegate controller. It ran great for a while but once things got warm it would throw PO236 left and right. I installed a boost fooler (resistor on intake sensor) and it worked to a certain extent but would still throw the code. Especially with a trailer. I then put in a reflashed pcm (see my sig) and it fixed all my problems with the code, defueling and weird shift points.