re. Error Code 2111 - No RPM Signal - Diagnostic Help Requested

[Ben Swann]

I'd like to know what you find, as I've seen this problem intermittantly.
 I assume the sensor needs cleaning, or poor connection - just haven't
gotten around to dealing with it, and there is no aparent problem.

Ben

[OK.  Friend's car ('88 5kTQ) that used to be mine.
When I had it got the 2111 and as a result replaced the sensor.
Everything was fine until recently when he started getting intermittent
2111 and the check engine light flashing.

Now he gets the 2111 constant.  Car is running like crap.  Stumbly and no
power until 4kRPM and then woosh.

What is the diagnostic proceedure on the RPM sensor?
Replace with known good might be an option, but now I'm wondering if the
problem might be wiring/ECU.

Please advise.

Rob D.]