I have been having (as many others have) an annoying engine knock. Mine occured only at idle and only after the engine warmed up. I read on another site that there has been success in getting rid of the noise by retiming the cp3. I tried it and I am happy to say it seems to work.

First off there are different causes for an engine knock, mine was a metallic sounding knock from the front left side of the engine. To change the timing is pretty simple. First remove the belt from in front of the access hole on the timing cover in front of the CP3. This will give you access to the nut that locks the timing gear to the CP3. Remove the nut and washer behind it(being carefull not to drop either inside, doing so will require much more work). Next you need a puller, steering wheel puller or small T bar will work to pull the gear loose from the CP3. Depending on how much dexterity you have you may or may not need to remove the upper radiator hose and bracket under it, in order to attach the puller to the gear. The fan is in the way of a standard length pusher bolt so I cut mine off, if you dont want to do that you can remove the fan. With puller installed and pusher bolt in place remove the gear from the cp3. The gear is a taper fit with no key way, so once the gear is loose all you have to do is rotate the engine to retime the cp3 in relation to the engine. I did mine twice before I found the magic spot, but it ended up about 60 degrees from where it was. Once you have rotated the engine re-install the washer and nut and torque to 77ftlbs(I used a ratchet on a dampener bolt to keep the engine from turning). Pictures are available in the service manual and will give you a good idea what is involved. It took me about 30 minutes to perform this procedure and I'm happy with the results.

Why does it work, well it seems that the cp3 being a piston pump behaves just like an engine, it takes force to push the piston on a compression stroke, and then after TDC it tries to spin faster(or easier) until the next compression stroke. When the engine is doing its compression stroke at the same time the CP3 is on its return stroke it can cause the gear teeth driving the cp3 to loosen and then slap back into contact causing noise.