KKersey

Bruce One question. Can you explain the windex or water method to check manifold temp? I have an inferred temp gun I use but have not heard of using windex or water.

Bruce Thanks for the reply. It turned out to be a cam sensor. Sounds simple in retrospect but I never saw one with those symptoms and got going down the wrong path with fuel pressure.

I have a 97 f-250 with 36000 miles on it which misses hot and lacks power after about 10 miles of driving with 12000 pound trailer. My question is on the fuel system pressure, it starts out at about 55psi then the guage fluctuates rapidly. When it is fluctuating it starts out with an average of 55psi then drops to 20psi average. No air in fuel system, 2inhg on suction side. No oil aeration, no codes, passes cyl.contributiion test, substituted IDM, switch box will not pinpoint cyl. while miss is occuring, however if you kill 6 it smoothes out engine. No noticeable valvetrain issues. Lift pump was replaced and fuel pressure was pretty stable at 60psi for about 10 miles and now it acts like the old one. Regulator has also been changed. Best I can remember the guage fluctuations are normal but I dont think the drop is ok since the spec is 40-70 psi. I also installed a spacer on the standpipe to be sure it is fully open. Return fuel seems limited when ran into a container, about 1pint per minute.Any ideas or fuel system info that I have missed welcome.