Originally Posted by Leithalweapon
I have a 2006 Solstice with the stock 2.4L (22,000 miles). The idle is a little rough. Sometimes it seems like it shudders or misfires. I always use high octane fuel. Although I bought the car used with 20,000 miles on it.
The simplest thing is to make sure the car has the stock plugs, properly gapped. The previous owner might have substituted some other junk.
Secondly, don't let anyone talk you into using "seafoam", or some such similar
crap in order to "clean out" the top end. The only thing that will clean out is your wallet.