I have just recently bought a 2000 Mazda Protege 1.6L w/ manual transmission. It has been making more and more engine noise and I'm getting nervous about driving it much more until I fix the problem. Its ticking regularly from the top end which I imagine is lifter taps but it also has a heartier ticking every so often and I can't quite locate it.. when I pull the throttle cable and release it I can hear a noise that is difficult to put into words (maybe like the last bit of water leaving the bathtub) it seems to be coming near the airbox. It seems to be losing power, and when I come to a stop the rpms surge and stabilize and surge again.. when driving, it almost feels as if there is too much friction somewhere in the engine that keeps it from going the speed it wants to go.

I was changing the original spark plugs, the first spark plug boot broke apart, got it out no problem. plug 2-3 werent a problem but #4 came out with the threaded sleeve which I was able to get off with no damage. I put medium locktite on the threaded sleeve, anti sieze on plug and sent it in, checked it when I got home and its still snug. Replaced the spark plug wires and that's when I noticed more of the noises.. also the pulley on my power steering pump is a bit loose, hasnt seemed to affect much.
I was planning on cleaning the throttle body, the IAC, and the EGR as well as the oil, transmission fluid, PCV valve, and a few others

I got a valve cover gasket so that I could look inside the top of the engine but to be honest I need some guidance on what indicators I can look for when I get it open.
Also any thoughts on dropping oil pan/pump and checking in the bottom of the engine?
Please, I am open to any knowledgeable guidance or direction on these issues. Need to get em fixed asap..