This last December, I got the following Cel, 16396 bank 1 camshaft A intake setpoint not reached (over-retarded). I had a valve cover gasket kit in hand so I took the drivers side cover off and discovered that I had lost the antifriction pad on the Cam chain tensioner. From what I have read, when a cam tensioner goes bad, the engines make allot of noise, like a diesel engine. Mine did not make any extra noise.
I STFA and found nothing on replacement pads so I had to buy a tensioner. My car is a 2001 4.2 so the tensioner set me back 500.00! I installed the tensioner and had some problems with getting the cam sensors to quit throwing codes. Ends up that the drivers side cam chain and the passenger side cam chain have a different number of links between them! Drivers side is 15 and pass side is 16. All you 4.2ers put this in a safe place for when you have to remove a cam!
Since doing the tensioner change, I noticed a listing on ebay for tensioner pads from a company called The Import Experts. I got hold of this company and asked if the pads would fit a 4.2 tensioner. They listed fitment as 1.8 and 2.8/3.0 engines, but not the 4.2. I sent them my old tensioner to test fit their pads and the pads fit the 4.2!
So if any of you are looking for tensioner pads, give these people a call. They will save you a ton of money if you only need pads. Still no one is making an aftermarket tensioner for the 4.2.