What happened at Midway was luck to a huge degree, and excellent code breaking. The Japanese also had land based aviation sources to draw from during Coral Sea, adding an extra carrier if you will. Four US carriers would likely have been discovered earlier by the IJN, who had more, and longer ranged search assets. History shows the IJN was very good at finding ships. Considering the Japanese aircraft generally had better range then their US counterparts save for the Val, which still out ranged the F4F, the IJN could have been launching strikes well before the US could. The F4F had very short legs, and had the IJN discovered the US first, which is entirely reasonable, the USN would either have to send off strikes unescorted, to lose a lot of assets, or fight their way to within combat range of the F4Fs. The USN at that point was very bad at strike coordination, and there's no reason to believe they would have scored anymore than they did originally. The USN also did not employ CAP well at all, never enough numbers, and usually tied to their own ship. If Midway taught anything, numbers don't always carry the day.