Well before I popped the hood my first thaught was a rod knock or busted fly wheel. He said the noise had just started, and they had just changed the oil. When I open the hood we could tell the noise was coming from the right side of the engine. Not for sure what this could be. (hard knock) could a damged injector make this type of noise? Maybe loose / busted valve train? One thing Im sure of it does not sound like its going to go away on its own. Thanks for any help.

 

If it sounds like a rod/busted valve it could be failed o-rings on an injector. I had that happen on my '96. Does it smoke really bad?

 

Could be bent pushrod, broken rocker arm, broken valve keeper...

Need more info then what you gave.