Hi guys I'm new here. I have a 2005 cobalt 2.2 ecotech auto. with a R-title cause it was wrecked. When I first got it it had around 56,300 miles, now a few months later it has 58,500 miles on it. Now after 2,200 miles I'm having some problems with the car it would start up but run rough the " engine reduced power " would come up in the message data center. I would disconect the battery and sometimes it would start back up and be fine sometimes it would take more than one try. One night when it did this it would not start I tried disconecting the battery and even pulled all the fuses and relays out of the fuse box beside the console but it made no difference. I ended up running the battery dead trying to start it, I had to call to get a jump then it started up just fine. I drove it home let it set about 3 days when I tried it again the battery was dead so I got a new battery and put it in. After putting in a new battery it shifts harder than before. sometimes when it starts it still runs rough and the " engine reduced power " comes up in the data center. I will disconect the battery then reconect it and it will start fine run fine till I shut it down. The next time you start the motor it maybe fine or it could start rough and the " engine reduced power " maybe showing in the data center. I have taking the car to advanced auto and auto zone, they both told me that the mass air flow sensor, bank one O2 sensor 1 , bank one O2 sensor 2 , and the evap emissions canaster purge soleniod valve needed replaced. Could these or would these all four go bad at once ? Does anyone know why my auto tranny could be shifting hard ? would these sensors cause that ? I don't know if this would have anything to do with it but I received a recall for the steering ? Sorry for such a long post, just really getting fed up with all the problems with my car, it was good for the first 2,200 miles now It's getting old fast. thanks for any and all replies.