I am working on a:
1995 Mitsubishi Eclipse, 2.0 literWhen 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.