Hey guys I have a 2010 screw fx4 with the dreaded 5.4.. Just the other day it started to have roughly a a 3 second period where it would rattle on startup.. Also at right around 1800 rpm it will randomly hit a different exhaust note for a few seconds.. (possibly a bad cat?)
Not very impressed with the pickup since ive owned it a year and already sunk about 3000 into it.. Rebuilt the whole front suspension and 4wheel drive Passenger side exhaust manifold etc etc
Anyways any insight on my issues would be much appreciated

 

What brand of oil filter are you using and what weight oil?

 

Motorcraft 5w20

 

Motorcraft oil filter?

 

Yea I'm pretty sure it's a lash adjuster loosing its prime

 

Reason I'm asking about the oil filter is the anti-drainback valve. Motorcraft filters have good ones, others not so much, especially Fram.

Could be lash adjusters, but it could be cam chain tensioners.

 

Ya It sounds to high up and back to be the chain guides or tension era I'm thinking.. problem is it only last a couple seconds and has to sit so long before it will do it again

 

Does this engine have an timing chain tensioner that is kept tight by oil pressure? If so, that is the problem it would appear to me.

My Mark VIII Lincoln had this problem which was a common problem with that engine. If it sat for a few weeks without starting, it would rattle until the oil pressure pumped up the timing chain tensioner.