Honda Repair: 91 Accord S blink/Check Engine combo, nick nick, speed sensor

Question
Happy Labor Day to you, Bill!

I've got a fun one:  

My '91 Accord LX has been running fine throughout all this (although I haven't driven it much since these symptoms started).  It's a 4-cyl automatic/power everything, with 171,600 miles.  I've had it for five years, started driving it at 100k, and have never needed any major repairs.

Immediately on starting, the "S" light began to blink, and shortly afterwards I noticed that the speedometer/odometers didn't work (although the tach was fine).  The speedometer/odometers were intermittent at best for the 45 min or so I was on the road.  

On starting up later in the day the Check Engine light came on along with the blinking "S", and now both happen each time the car starts, a few minutes in.  It began to idle rough at 200-300rpm, but hasn't stalled out.  It seems to drive fine otherwise, I've noticed no difference in sound or handling when the car's moving.

In short:  "Huh?!"

Thanks for your input!
-Nick

Answer
Nick:
Yeah this is a fun one. I would start out with checking the code that comes from the computer, of course that will only give you the symptom of the problem but it is a start.
I would check the speed sensor to make sure that is good, it can cause the rough idle and the speedometer problem.
Good luck.
Bill