Have you checked the cam phasers timing chain tensioner cause this is how mine started out and got worse!!

Don't mean to high jack your thread but didn't figure a need to start another...

My sons 08 5.4L 3v was blessed the other evening with a CEL... The 5.4L runs fine, but it has a vibration or shake when the truck is at a stop and in drive with the brake applied...

It does not have the vibration when the truck is in park and at idle or reverse... It was checked with a snap-on code reader and showed a random misfire--I didn't ask for the code # I was in a rush--My Fault...

Have any of you heard of this or have any idea where to start?

New Motorcraft plugs were installed 5 months ago with boots... Truck has ran flawless... Lots of power smooth as silk...

Just had the 5.4L scanned... It showed a P0300 code---Random Misfire Detected Can any of you mechanically inclined fellas give me a direction to start looking?

I will take the truck to our mechanic Tuesday morning...