300SE Vapor lock??

[MB Neo]

My car has all the symptons of vapor lock. I stopped driving it in July because the heat just seemed to be affecting it. THe car would die while driving - any speed. Sometimes it would restart right away, other times it would take 5 or 10 minutes. I was told that it could be the fuel filter or pump. The pump hums nicely. I changed the fuel filter. I took it out today & while it did not die right away, after I got to my destination, it would not restart. It took around 10 minutes before it started & on my way about 100 feet it died while driving. 10 minutes more before restart & the car was fine the rest of the way. THis is very frustrating not to mention makes me very hesitant to drive it because I feel like I'm going to get stuck. Any clues as to what this could be??