Two questions about my 2000 5.4:

My 5.4 is making a clicking sound when the engine is cold, but it only makes it when I put the truck in gear. When it is idling in park it is not noticable. Could it be the infamous exaust manifold leak or is it a valve or rocker arm. After the engine gets hot I do not notice it. I have 150K and run 5w30 Mobile 1 synthetic.

Also, the other day it was very hard to start, acted like it didn't want to turn over. I let it run for a few minutes, shut it off and it started right up no problem. This is the second time time this has happened. I'm thinking a possible mass airflow problem. Am I on track or way off and if so what's a solution??