`90 80 diagnostics

["Dmitry V. Goloubew" <dmg@culture.ru>]

Hi!

I've conducted MonoMotronic diagnostics procedure which shows that hall
sensor become inoperative (code 2-1-1-3). But the engine still starts
and works fine, fuel consumption does not exceed usual amount, and
everything seems to be fine except when I release the accel. pedal being
at 1st or 2nd gear the engine loses RMPs not steady but with a little
jerk. Same happens at higher gears too but not so sensible. May be there
is some kind of weak contact in wiring? What could it be?