SoCalSL

Three or four times over the last year my car has gone into limp mode, almost every time while driving on the freeway. No errors on the system display, turning the car off for a minute or two and starting it back up gets it back up and running. The first time it happened I had it checked and there were no stored codes. I also had them check the harness to make sure fluid wasn't leaking and getting pushed up into the control module. The other day it happened twice in about a 30 minute time span and I'm getting concerned.

Any advice as to where to look? Could inconsistent voltage from the alternator cause this? I notice my dome lights and dash lights will flicker (for lack of a better word, not off and on but the consistency of the brightness noticeably changes). I had the idiot dealer check that just last week and they found no problem. The light problem disappears when the motor is off.

Thanks in advance.