Motor noise

[jimsitasca]

Hi all, I have a class C, Itasca, E350 with a 460 ford motor. This is a fuel injected motor with 75000 miles, motor is making a pulsing sound when accelerating, this will stop when I let off of the gas, the motor runs very smooth at an idle. There is a new fuel pump in tank, new fuel filter and new fuel regulator. Hoping I can get some help on this problem because I am going to install a new or rebuilt radiator an want to get this problem fixed at the same time.
Thank you for all of the information that I might get.
Jim

[twinboat]

Check the exhaust manifold gaskets and for a loose spark plug.

Shoot a little oil in the intake, while running, and watch for the smoke leaking out.

[jimsitasca]

Thank you, I will check for an exhaust leak and loose spark plug. It just does't sound like an exhaust leak, there is no ticking sound like a normal exhaust leak. I am going to have the motorhome smoged this morning and will have the mechanics check for that.
Thank you
Jim

[jimsitasca]

I checked the exhaust and found no leaks, all of the spark plugs are tight. I am going to look into the clutch fan to make sure there are no problems with that.
Thanks for your info