Car engine shuts off while driving on 1999 Volkswagen Passat

My car engine has 1.8T automatic. I had the problem three times in last one month. The engine shuts off when I am stopped on a stop light, the car shakes like 2 sec before it shuts off; and it restarts immediately by turning the key off and then on. I talked to a mechanic and he said there might be some water in your gas tank or some sludge in the system so he put some cleaner in my gas tank and said if that was the problem it will fix it, but it didnt work. I told him again then he said until the CEL goes off we cannot see the code and cant figure out the problem.

Does anyone know what might be the problem or someone has the problem before. To me it doesnt seem like any electrical problem because when it shuts off I feel like it ran out of fuel or something.

Asked by for the 1999 Volkswagen Passat
Given the year and model you may have a failing fuel pump. Assuming this is a Gas engine.
I would still try positively diagnosing it i.e. monitor fuel pressure with a gauge at idle first.
The electrical portion of the ignition switch is a possibility as well. Spend a minute with a scan tool if you can......
2 more answers
Just had this problem occur this week. It could be the MAF (air meter), which controls the fuel mix. Cost at the dealer was $204.75 plus $285 labor. Ouch! $504 total. Reading what the mechanic did to test it, he unplugged the MAF and it ran strong, so I'm wondering if this part is essential or not?
well on this car as of any that is 96 and above the problem needs to happen three times in a roll to set light how ever two is enough for code to set in computer without light comeing on have them hook up code reader bet code is there