I can't seem to figure this one out - can someone help?

My idle is running rough (I can hear what seems to be misfire coming from the exhaust), but I don't think I have any power loss when I get the car rolling - and it doesn't vibrate during driving. I've changed the wires, but I haven't looked at the cap/rotor/plugs just yet. It almost feels like I'm going to stall, but not, and the trouble is I have a 97 DX (just turned 90K miles!) so there's no tach to tell me if my car is surging or not...anyone help?

I've heard all sorts of issues, like a vaccum leak, or a fuel sensor going bad...I'd like to figure this one out before I have to go to a shop that'll charge me for just figuring this out...thanks!

T-X