I really hate to say this, but take it to the dealer. I know a lot of people on here (myself included a few years ago) are gung-ho against dealer wrenches, but I'm going to give you my reason why.
Back in late 2009 or early 2010, my 06 Cobalt LT threw a code. My hubby is a body guy, so he took it to a wrench friend of his to get the code read without paying a $50+ diagnostic fee. (My hubby's OBD reader hasn't been updated and couldn't get a read off of it, or he'd have done it himself.) It was the code for the throttle position sensor. It had been stalling out at low idle before the code was thrown. Wrench said to ride it out. Few wks later it came back, and we replaced the throttle body. Still stalled out. To make a long story super short, over the next 2 years, she developed a misfire (a SHAKING misfire at times). We changed plugs 2x (once with autolites, once with AC Delcos), tried dry gas, 2 diff. kinds of injection cleaner, new injectors (which, if anyone ever needs them, Chevy did have a set of 4 for about $100 instead of $100 each!), AND a new coil pack. I also started running Shell premium (already ran shell, just used regular) gas. Nothing. Where is this car today? Sitting parked at my husband's shop. She's still being paid on, and we're leasing a 2012 CRV. When you start her up, she's louder than the 73 IH pickup my hubby just restored.
My mom had the same code pop up on her 05 LS. Lucky bitch (and I say this nicely - she is my mom after all!) was still under factory warranty, since she bought the thing new and had it extended to 7 years. The code popped on a Sun, took it to autozone to have it read (throttle position sensor), and by Mon, it was in the hands of the local GM wrench. They replaced the throttle body, and she has had no problems since.
Now, I don't know for sure that me "waiting it out" caused more problems, or not. Hard to say. My code first threw around 63k miles. My mom's threw around the same time, just 2 years later. (She's 62, and doesn't drive much other than to work and back. Maybe a trip to Indiana or TN from Ohio to see family every once in a while, but that's it.) I'll be honest, though. Even though I LOVE the CRV, had I known that paying a little more and taking it to GM might have cured the problem, hindsight says that we should've bit the bullet and done it, especially since we're paying on a vehicle that's not even drivable!