88 SE CA18DE CODE 11 Crank angle sensor

[dougq]

Folks: I am hoping for some forum wisdom.
The symptom is intermittent inability to start.
If cold it starts ok, after shutting off and waiting up to 2 hours it will not start.
After cooling down for 2 hours,it starts and runs ok with code 11, Mode 3 in the ECU.
If I clear the code 11, I get 55 in mode 3, until the next failure to start.
What I have done:
CLean connectors on the CAS and the ECU, check the chassis and engine grounds (this made the problem go away for a couple of weeks).
I don't think I got all the grounds, so may revisit that.
Check continuity from the CAS to the ECU. Checks ok.
If I believe the code 11, I need to replace the CAS, local dealer wants $900.
I have not tried wreckers yet, after more ground checks that is next step.
Have I missed anything that doesn't require spending more than this car is worth. It is a lot of fun to drive, but not if you have to wait 2 hours to start it again.
I took the CAS off and thought I might check it out internally, but the screws that hold it together are designed to be tightened only. Not sure I want to hack them up to take it apart.

Any help appreciated.

TIA.