first of all thanks for your help! I have a 2000 blazer i bought with a bad motor i replaced motor with a used on(78000miles) it had no power converter was coming apart on the inside! removed converter and installed a thrush turbo muffler better but still dont seem right! if running around in town very long codep0327 comes up(knock sensor) if running at 55 or up it never comes on! I bought to pull my aluminum boat with and seems like it really struggles! It you mash the gas hard seems to do okay but have to really keep on it to keep up the speed(without towing boat) I had a 93 blazer and it seemed to be alot more powerful! I usually drive a V10 dodge and wanted something i could more afford to use as a hunting and fishing rig so i bought the blazer ! Sorry for the book but i figured details would help! also is there 2 knock sensors on this rig

I was driving it up a hill pretty long and steep it would surge have not noticed that before! Any suggestions on why it seems powerless or is surging i would appreciate it