Hello all, brand new to this forum and looking for help. I own a 2004 F150 w/ 5.4 3V and 141k miles. When I bought the truck it had a vibration/shutter that happened right around 2000 rpm. It happens every single time. I can replicate the vibration in PARK as well by revving the engine. Once I am over 2000 rpm it goes away. There doesn't appear to be a delay or hesitation while driving its mainly just an annoying vibration.

I searched the forum and most of the vibration issues are when people are driving so I am still scratching my head from where to look.
The previous owner said that he changed the spark plugs. I just had the cam phasers and VCT solenoids replaced (but the issue has been there before I had this work done).

Any advice?

 

Yesterday was the first day I put a heavy load on this truck, about 1000lbs of flooring. The vibration was significantly worse at the same RPM but there was no hesitation with the truck. The vibration was just much more noticeable. Any ideas where to start?

 

Maybe inspect the harmonic balancer? Loose flexplate? Remove the fan belt and see if it still vibrates. Just wild guessing here. I'd throw a couple bottles of Chevron Techron or Gumout for high mileage engines with PEA in the gas tank just for grins and giggles.