2006 colbot needs boost and runs rough engine light comes on.

I got a 2006 cobolt, I have had it about a yr, has less that 110K on it , A few days ago i went to start it and it was dead, We jumped it and started no problem , used it all wk end  no problems at all, Then on monday after a heat spell here in canada lots of humidity etc, i went out to start the car monday morning, would not start, gave it a boost and bang started but this time it ran rough real bad whole engine shaking  and engine light on , got it to my buddies garage ,he put the computer on it ,READ misfire, so it sat for about 1 hr before he got it in to the bay, well the car started no problem and was not shaking and ran perfectly so when he did another test on the computer  codes came back clean. So i brought it home, used it all day ran great , then this morning i go out to start it and again would not start, so i jumped it and drove to the garage we checked the battery ,it is good , car runs fine now but i no it will do this again and we cannot figure out the problem, Fuel pump works,