I am having a problem with a 2005 648 GIII skidder. It just had a engine rebuild 1 week ago and run fine for 4 days but then the copper washer broke on 1 injector so we changed it and after that it sounded fine but would bog down when you put it in a pull up a hill and slows to a crawl, only code is F477. We have tried everything that we know to try, here is a list of most of what we have done. Put all new injectors, changed fuel filters and air filters, blowed through fuel line back to tank, I think the problem is related to the boost and not fuel because we unhooked 1 boost line and it didn’t change anything still run the exact same with the line off, so we bypassed the aftercooler because thought it might be cracked but that didn’t work either. What could my problem be?