I have a 95 f250 7.3 that I converted to alt fuel . I changed out the mech fuel pump to a late 99 ele. pump for the front tank with the top of the timing cover, filter and factory lines to the heads with 1/8 in check valves in line , and at the other end of the heads, put in another set of check valves for the rear tank with 2 elect factory fuel pumps. these pumps are run with relays and toggle switches to switch from the two fuel sources. I put in a fuel press gauge in the front plug in the head in the fuel rail [drilled and tapped it to 1/8 npt] so that I can watch fuel pressure . the problem is that when starting ,one of the injectors must be leaking a small amount of compression into the fuel side because the gauge wobbles with the speed of the engine. It comes down in a couple of seconds,but it will destroy a 100 lb guage. the engine runs fine ,on all 8 when cold,starts in 1/2 second or so but I know that it has a bad nozzle . how do I find out wich one ?