I just bought a 2002 Dakota with a 4.7 V8 and it has a rattle or tick in the upper engine and at least 1 cylinder is a dead miss, any suggestions what this might be? I've just last night started reading that it could be a rocker arm fell off. Seller said that it was knocking but it certainly is not a rod or main bearing knock, more of a rattle or heavy tick. I need to mention that this truck has 236k miles.

 

Going to have to pull a valve cover off and inspect.

 

Definitely pull the valve cover. It could be the rocker arm but it can also be a dropped valve seat. Cylinder #2 is the most common for that problem.