Bottom Line-we were second owner of car-bought from GM dealer with 17000 miles on it-great shape. No issues until this cracked manifold-found out researching buying manifold to replace myself online and have called and spoken with dealer.. They indicate a campaign was initiated since this is a very common problem ergo the extended special warranty. BUT you have to ask. Was looking at a $250 min in parts and $350 labor.

Further research shows common problem during R&R is breaking studs or bolts and in particular one or two in "rear" areas. If this occurs the head must be removed to tap out the broken studs/bolts. This alone adds 1.5 to 3 days to job at dealer level and up to $1000 to job cost. Best for sure to use GM ezxtended warranty and let them deal with all this. They pay for and allow 1-day car rental in the deal with extended day or two car rental if they need to pull heads for broken off studs/bolts.

Took my car to a mechanic who could not diagnose the problem. Every time the weather got really cold it would idle really rough and shut off. my car kept spitting out random codes like multiple cylinder misfires, misfire on cylinder 6, and fuel to lean. Took it to the dealer where I bought it they sad I needed a new oxygen sensor and cleaned water off of my 6 cylinder. they changed the oxygen sensor and it still did not help so they put the old one back in and referred me to a Chevy repair place for a new fuel pump. Well the repair place had no clue so after multiple calls to CHEVY tech support and 5 months of aggravation my car had a cracked exhaust manifold, needed a new oxygen sensor and a new exhaust manifold gasket. Luckily chevy made good on my expired warranty because the exhaust manifold tends to be a problem for this year.