I have a 2000 Lincoln ls 3.9 but believe this problem is for 2001 also. It sounds like rod knock but it's not. Passenger side usually fails first it's the UPPER TIMING CHAIN TENSIONED, about 80.00 on eBay. Factory ones we're plastic and would break apart but replacement ones are all fine. Just remove valve cover, and remove can caps, hold Downs for cams. U just need to lift up one can in order to get old tensioned out n replace. Note notches on both cams n make sure flat sides are in same position on both. Replacing used cam bolts will break if tightened more than 30 pounds because they stretch and are not meant to be reused, but I did. Its sound hard but it's NOT! YOU have 2 arms and 2 hands like me so you CAN do it.

You can email me for better directions at Gari6167baldi@gmail.com. Mechanics wanna charge up to $2,000 for this, don't pay it, try it yourself. These are nice cars, just ahead of their time w a few issues. I have put 50,000 miles since my fix which was a new upper tensioned and new valve cover gasket. Getting the gasket not to leak was harder than the job. I love my car.