Vehicle will not pick up speed at start off it will not go over 65 and has a knocking and it sometimes won't start

Hello, the "knocking noise" sounds ominous; if it's in the engine area, it would seem to be that there could be an internal engine concern causing reduced engine compression, a timing issue, or worse. Hands on inspection is needed. Do not continue to drive a vehicle that has knocking and takes a while to get to speed! You will only make things worse than they are, not to mention cause a safety concern for yourself and others.