[Shotimes] 89 SHO Idle Issues - Help Please

[Mike Kelly (Test)]

Hello.

This would be my first post to your prestigious list.

I own a 1989 SHO that is very temperamental. I am currently having a problem
with the engine idle speeds.

Symptoms:

While engine is running, if I hold the clutch in, it typically revs between
1400 and 1800 continuously every 2 seconds or so.

After driving, if I put it in neutral and let out the clutch, it revs at a
steady 2500 RPM for a full 30 seconds before revving between 1800 and 2500
every 5 seconds or so.

Sometimes (though more rarely and possibly unrelated) going around turns, if
the clutch is in, it revs up to 3000 RPM, until I complete the turn.

I don't trust dealerships because of past pillaging, and I am not near any of
the recommended mechanics (Memphis, TN). Could someone please let me know what
could cause this, so that I know what needs to be fixed before allowing it to
be worked on.

Thank you,

Mike