Engine stumbles and hesitates, wierd noises

[legendarysnail]

My '93 coupe has completely craped out the last couple days. When you push in the clutch (ie. coming to a stop at a red light) the engine will flirt with 0 rpm and sometimes die. When it doesn't die, it idles between 450 and 500 rpm. Called a friend (not an import guy) who suggested the throttle position sensor, but another guy said something in fuel system was giving out.

Also, ever since I removed my upper chain guide a couple days ago, I can hear this metallic 'scratching' sort of sound coming from the engine. It sounds like brake pad squeal, but it's from the engine (changes with engine rpm). I can also hear what I think to be to upper side guide rubbing on the chain (sounds like the upper guide, but lower down). Could the starge noise be the side guide, or even the lower guide?

ALSO..........there's a tapping noise coming from the 3rd cylinder area...might this be valve tap? Is it a problem I should look into in the near future?

ALSO.....(ugh)......the car stumbles/hesitates severely when accelerating normally (only does it a little under WOT). I thought it was a clogged catalytic converter, but I'm also considering that it could be in the fuel system.

Can anyone help me figure what what my problems are? I don't wanna invest some money into this engine if it isn't worth it. I'd rather buy a newer engine/tranny with lesser miles.

Thanks in advance!
- Snail!!!!!! (>_<)