I have a tapping noise that sounds like it's coming from what appears to be a distributor, on the passenger side of engine. The noise goes away once the engine warms up. Is this the opda ? I've done some reading on the forum and I think that is what it is. Haven't had a lot of time to research, too busy with other things. If so, is it difficult to replace ? Is this something I can do or should I have a shop do it? I have a fairly good mechanical background, but this is my 1st Jeep and I've only had it a few months. Not real familiar w/this type of system. Btw, it has 66k on it. Thanks.