I am working on a:

   1995 Mitsubishi Eclipse, 2.0 liter

When cold, the car idles nicely.

As it warms up, the idle RPM cycles up and down.
As it warms up, the amplitude on the upside
increases. Say the cold idle RPM is 800.  As it
starts to warm, the idle RPM will cycle between
800 RPM and 1000.  Then this increases steadily
to between 800 and 1200, and keeps increasing.
Eventually the upside RPM gets over 4000 RPM at
idle.  

The length of an up-down cycle is only a couple
of seconds.

While all this is happening, can see on the scan
tool that the idle air controller (IAC) is
cycling up and down.  But other PID's look
normal.

Also the MIL comes on.  But the cycling begins
first and the DTC's are not set until the upside
RPM is well over 1500.  The DTC's are:

   P0340.  Camshaft Position Sensor A Circuit Malfunction
   P0505.  Idle Control System Malfunction
   P0352.  Ignition Coil B Primary/Secondary Circuit Malfunction
   P0351.  Ignition Coil A Primary/Secondary Circuit Malfunction
   P0113.  Intake Air Temperature Circuit High Input
   P1294.  Manufacturer specific code

Have already replaced IAC motor, cam sensor, and
ECM. The problem still persists.  Also
temporarily disconnected the PCV hose.  Have
checked for vacuum leaks and found none. Spark
plugs and wires are reasonable new.  The problem
still persists.

Removed and reinstalled the crankshaft position
sensor (CKP). Did not replace it yet, because
cannot keep on paying for new parts and get no
results.  The CKP had oil splashed on it when it
came out.  Is this normal, or the symptom of a
problem?

Has anybody seen this problem before and know
the cause?

Jim S.