Driving my 1990 5.8L F150 today (very rarely driven) I noticed a rattle every time I accelerated from about 35mph up. Sounded like a bunch of cans of spray paint being shaken up, but would stop when I took my foot off the gas. Should I adjust timing slightly or check something else?

 

Yes, I would check the timing and if it is anything over 10 degrees before top dead center retard the timing. Don't forget to remove the spout connector.