i thought i was going to replace the valve cover gaskets in my montero come to find out all they need was to be tightend down so i put the throtle body and everything back on and together it starts up just fine but now has a good awefull noise coming from it. it sounds like a valve went to **** on me sounds like something rattling around underneth the valve cover what is causing this and why when i never messed with none of that?

 

Why don't you pull off the valve cover and take a look?

 

lifters.

 

Could be a stuck lifter.