the old PGM-FI thing - i have 87 honda prelude
 

My car has the good ol' PGM-FI dash light on problem. This seems to be
a common problem and I have seen a variety of explanations.

The light normally comes on when you turn the ignition key and
immediately turns off after I successfully start the car. However,
after I drive the car for 15 minutes, the light comes back on again and
doesn't turn off until I turn the car off. This is not normal. When
I start the car again, it will stay off again for a few minutes.

I have seen a number of explanations for this:
1) bad oxygen sensor (replace sensor)
2) problems with the solder connections on the main relay (replace
relay or re-solder all connections)
3) put fuel injector cleaner in the tank or get injectors cleaned

I understand the ECU might help me figure it out. But then I also
understand that the ECU is sometimes mistaken.

Any help would be much appreciated. My car stalled out today. I think
it was due to a problem with the ground wires but I'm still pretty
concerned.