If you still getting a rattle with a motorcraft filter and motorcraft 5w20, then next oil change throw in a quart of 20w50 and 6 quarts of 5w20 (if you have a 5.4 that takes 7 quarts). That lucus is like gear oil it will boost up your oil weight and most of the ticking/ rattles will go away. Sometimes I wonder if it just isn't rebottled gear oil.

Tried the Lucas Oil Stabalizer last oil change. No better. This oil change I went to a more expensive K&N filter for the chance of a better anti-drainback valve. no better. Next change will be with full synthetic. Cross your fingers. Blasted thing sounds like a diesel when you first start it up for about 1 second. Only has to sit for about an hour for it to happen.

The cold start rattle can be for several reasons and none of them hurt anything (except the oil filter). It can be a slight piston slap, leakdown of the timing chain tensioner, lifter or injector bleeddown, off brand oil filter, etc. I've sold vehicles because I worried about the rattle and they are still running strong hundred of thousands of miles later.

Changing to expensive oil, thicker oil or snake oil enhancements do no good. Thicker oil may actually shorten the life of the engine. Engine bearing wear happens after the engine is started but before the oil light goes off. Thicker oil takes longer to get to the bearings and as a result, the bearing is dry longer and gets more wear.

STP in the Blue bottle...works great, plus adds ZDDP, one of the most important high load additives.