[Superman]

This may come across as stupid but have you taken it to a shop, they do free comp checks. maybe they can plug her into their computer there and find an issue. I would try checking your sun visors or maybe check the halogen levels in yer lights maybe they need refillin. ;p But really good luck with it. I hate it when I have an issue I just can't pin down.

PS
I called the X wife about the issue with her Celica and turns out she totaled it a week after she left me. hahahahahahahahahahaha! Gotta Love it.