I edited out some of the garbage from this one!
Please play well in the sandbox, children.
But really.
I don't guess at these situations because the engine could have one of a hundred things going on that should be looked at by a qualified tech!
Also, I would get the ECU flash done, but I would not replace the ECU. Some of us outside the dealer/warranty situation have to pay over $1,000 if we wanted to "just replace the ECU" to guess at what a problem might be.