94 prelude problems with idle and startup?

I have a 1994 honda prelude with the JDM 2.2L VTEC, and it has recently been giving me some problems. After driving it for a while it will just shut off, and then turning it back on is difficult if not impossible. If it will turn back on it starts up sounding like a go-kart, and will idle around only 500rpms. I brought it to a garage and the mechanic said he didn't have too much time to look at it but offered some Solutions for me to try (for free). So I changed the spark plugs and ignition wires. In doing so I saw some oil in the spark plug wells. So I replaced the valve cover gasket set. It still does the exact same thing. I believe the culprit to be the idle air control valve. If this makes sense please tell me, and if it doesn't make sense please offer some helpful feedback.

Thank you.