I would still take it somewhere that has a capable scanner that can read all codes, looking for any stored or pending codes.
If there are truly no codes found, just fyi - on my '06 I have had a failing crank position sensor cause issues without ever setting a code, and a 2nd one do the same until it eventually did put me into limp mode and set a code. There is also the possibility you have a failing input speed sensor that has yet to set a code. Had that issue, until it became more frequent and did eventually set a code.
Worst case, you may need to find a shop that can hookup a scanner that can data log, and when it occurs again, go back to the shop to have them diag the results.