Actually there is somewhat of a humming vibration from the car at certain rpms. I am not sure whether it is normal or not, but I have this feeling it's not.
It's quite weird, because the humming vibration comes and goes. For instance, it's present at 1,500rpm, 4,000 rpm, 5,000rpm and maybe some other particular revs.
The vibrations are very slight, and not noticable, and there are no vibrations when I let go of the throttle.

Techron I assume is a particular brand of fuel system cleaner fluid?

__________________
Smoke Silver 1994 E220 Coupe Automatic
0 kilometers 6 September 1994
100,635 kilometers - 6 September 2010