i am having problems with knock and think i have it narrowed down to the fuel pump. i have around 40psi fuel pressure and as soon as i get on it the pressure rises to 55 or so then as it starts boosting the pressure falls back to 40 and stays. it is a walbro 169 pump that is 1 1/2 years old.Also has the hotwire kit. Could it be something else besides the pump?? Thanks