a flickering check-engine light

[Phil Rose]

started this morning. The light flickers briefly (numerous times for
just a second or less, each time) while driving. It appears to be
related to abrupt chassis movement (driving thru potholes, bumps,
etc.). The ECU fault code is 2111 (engine RPM sensor). This value is
seen while engine is *running*, so it's evidently not just that
"false" 2111 that is commonly seen when reading codes with the engine
stopped. The light flickered during just the first 30 miles of our
drive today but then was OK (no light) during the last 120 miles of
the trip.

I have now done all the specified electical tests at the speed sensor
connector (a la Bentley), and everything so far checks out OK (I've
not done the continuity checks back to ecu--ugh).  Also I guess it
wouldn't hurt to clean up the manifold ground connections. Anything
else possibly causing this symptom?

Phil
--

Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net