plugs look clean, boots are not dry rotted from heat dont see any sign of arching?
i have sudden misfire of 2006 cobalt 2.2 ecotec engine 1002000 miles car ran fin on 2007 Chevrolet Cobalt
Any check engine light or codes stored? Does it miss all the time or just when cold, hot, under load? A little more info would be good for me to help. There have been coil issues and some injector issues. You will need a scanner (not just a code reader) for diag.