ABS lights appeared the interior and exterior lights dimmed and the car got sluggish?

The first time my problem occurred was during a snow storm in mid-December 2005 I was driving and about 20-30 minutes into my trip I heard a pop in my radio like static the fuel and abs lights appeared the interior and exterior lights dimmed and the car got sluggish. All of this lasted about 10 seconds accept the lights they lasted about a minute or two and then everything popped back to normal. It did this for the last hour of my trip in 5-10 minute intervals. It was also stop and go traffic and I had my wipers, headlights, radio, defroster and rear defroster were running. I drove it to my mechanic and the car never did it the next day and no codes where found diagnostically.

Since then the problem has occurred intermittently about once or twice a week usually gas and abs light pop on and disappear right away. But, I have also noticed that the gas gauge will dip from a full tank down to half and then it will very slowly crawl back up to full.

The car has been in and out of three shops and nothing is showing up diagnostically, it has only stalled once during this time and it started right back up. Also, the problem never occurs on the highway, it is always in stop and go traffic. The worst it has occurred was during the snow storm but I have driven it through sleet and heavy rain and it has never occurred during the wet weather since.

Can someone please help, very frustrated with this situation.