My 2009 has been giving me starting problems for almost 2 months, Hard starting as I had to floor it in the mornings to get it to start then having to keep the rpm up over 1500 for 30 - 60 seconds and it would start running smooth and not rough. 227,000 miles on her so I changed plugs and wires throttle body, maf sensor along with new air filter over a month or so. It started a lot better but still have to hold pedal down ( like its flooded ) but it smooths out within 10 seconds or so then will idle without stalling out. I then started thinking it may be coolant leaking into one or more cylinders and I had to floor it to clear out the antifreeze before it would run smoothly. It would put out white smoke when starting. So I put some head gasket sealer stuff in it and it got much better but not good. Is there a way I can determine if its the head gasket or the intake gasket which if it's the intake gasket that would make life easier. A friend told me that impalas had problems with intake gaskets so changing that would be much easier than having to pull the heads too. I didn't use much coolant and I've never overheated the car. also it's a 3.5 flex fuel and has been running great until...then it kicks out a code bank 2 rich.