Messed up cost basis, should I file a 1040X?

[taxclueless]

I messed up the cost basis for a stock I sold in this year's return. I thought the proper thing to do was to file a 1040X, an amended return. But after reading through threads in this forum, I'm not so sure. There are posts saying to wait until the IRS catches it and then respond since sending in a 1040X messes things up? I don't know what to do now. Should I file a 1040X to correct the cost basis?