I've checked the codes on my 1987 Oldsmobile Cutlass Ciera, to see if I
could find anything wrong with the Transmission, or Timing, because the
car's a little sluggish, and there is a fair amount of spark knock.
  Here are the codes.

 12-- Diagnostic Mode; No Distributor Signal to Electric Control Module;
System PASS.
 25-- Manifold Air Temperature (MAT) Sensor or Circuit voltage low or
vacuum switching valve problem or ATS sensor fault.
 42-- Electronic Spark Timing (EST) circuit fault or fuel cutoff relay
circuit fault or Direct Ignition System (DIS) fault.
 What do these mean, and What should I do to fix them?    Should I erase
the codes, and then see if any come back?

         Thanks

                 CRC