Getting a miss

I notice it mainly at idle. I think i feel it while moving but it could be in my head. I also get the idle going up and down at idle. ICM? What is arching and what causes it? Thanks.

Ohh man I hated that when it happend, you probably need a tune up.

1 ignition problem (rot,cap,wires,ignition mod,pick up coil,bad ground, plugs)
2 vacuum leak (o rings, gaskets, hoses)
3 bad CTS switch, some other sensor causing the ECM to react to your idle, MAP
4 low compression on a cylinder
5 internal poblems (lifters, etc)
6 IAC valve or connection
7 other


Connect a vacuum gage to it and see what that does