99 E300 switching OFF

[joel_E300]

Hi,
The 99 E300 diesel seems to switch off when I stop in the first few stop lights (when the engine is less than 80 degrees). However it starts immediately in teh first attempt.

Any suggestions on what may be causing this and a possible fix...?
Should I try some fuel injector cleaners... or would it be some air bubble in my fuel system...?

Thanks for ur help in advance.