So I have a 5.4 3v owned since 36k (Feb 2009) and now at 101600. Truck has been extremely well maintained and runs strong now especially after changing my VCT solenoids. Here's something I've noticed lately however:

In February, I noticed a light tapping one day. It's not injector noise, I know and like that noise. This one comes and goes. I thought it was a manifold but it came back recently. When pulling into my Uncle's house yesterday I was going up a hill and the truck downshifted (only going 10mph or so) and the ticking was loud next to park cars then quieted down as rpms dropped. Usually when I hear it, it's at cruising speeds and rpms are low - say 1000-1250. Is that engine related or a manifold? It's a tapping sound for sure and like I said, comes and goes. When I left hours later, the sound was not there.

 

Any signs of sludge build up ?

 

When I pulled the solenoids IR looked very clean. Nice thin coat of oil no build up. Today very quiet

 

Anyone else have any thoughts? I haven't seen any codes or noticed any drive ability issues. I'm thinking unless something happens, just live with it. It's coming from the passenger side for sure. It does go away when I shut it off though and doesn't necessarily do it when I turn it back on. Kind of makes me wonder if that's an oil pressure issue.

 

Anyone?

 

I decided to change to Mc synthetic blend 5w-30 instead of the usual 5w-20. Truck is quiet as a church mouse. I don't think I've ever heard it run so damn quiet. I'm hoping this continues. It seems like it's running smoother but I don't want to comfirm anything so soon in case its placebo.