Intermittent pretty well lets out the mechanical side. Our MB's usually work or dont.

You might consider pulling the tank and having it flushed. The borescope is a good idea too.. get an idea whats happening in the tank

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."