[s-cars] Blink Code 4421 = No. 5 injector

[Dave Forgie]

One of our Vancouver club members has got this code (naturally after I
test drive his car to diagnose an "electrical"/ignition-based miss -
which there was none).  I have suggested that he should first make sure
the electrical connections are good and clean. If he still gets the
code, I have suggested that he replace the injector (original 95 S6). 
He is now asking me about having the injectors cleaned.  While getting
them cleaned is generally a good idea, I am skeptical that cleaning
would solve an electrical issue within the injector.

Any thoughts?

Dave F.