2000 GMC Jimmy has some engine clicking?

I bought a 2000 Jimmy last year in january and it ran perfect you couldnt even hear it when it was in idle but now i hear alot more noise from the engine like its working hard and it has some quiet clicking to it (in idle) I am wondering if all this is normal and if there is any way to make it go away any ideas would help thanks.

and....why is this in the camaro section?

Could it be dirty oil?? I know the lifters in some cars make a clicking noise as the oil begins to get dirty.

sorry guys im new with this site i posted the wrong car in the wrong category but fi you know the soltuion id apreciate it sorry again

hmmm jimmy is the same as an S10 blazer right??? if so, its one of two things, when its making the noise, put your hand on the PCV, ill bet its vibrating like mad, pull it out, bet the sound goes away. if it does, replace the hard plastic line connecting the PCV to the other thing it connects to lol, dont remember right off the top of my head. replace it with a 12in section of rubber hose of the same diameter. should fix it. if its not that, check the fuel lines as they come up the firewall from under the vehicle, they are known to touch the chassis, and you hear the pulse of fuel going through the lines, sounds like a ticking from the engine. drives ya nuts trying to find it. you have to pull the lines away and put a foam rubber spacer between the lines and the chassis. if its not either of those, could very well be a loose rocker or something. those are the two items that im familiar with being a chevy tech.

could also be a leaky manifold gasket