420A 1998 420a all cylinder random misfire

[xnol1m1tzx]

Hopefully I can figure this thing out with everyone's help and not replacing every part with no change I get p0300,0301,0302,0303,0304 all at once
I suspect a sensor/cat/or ecu don't know what else could possibly cause it with no symptoms

I have a 1998 eclipse gs 218k miles
So far I have replaced;
-Radiator/hoses/thermostat 180*
-valve cover gasket (internally was very clean)
-NGK v plugs gapped at .038
-Bosch wires all tested less then 4k ohm
-new coil testing within spec
-put oem air box and filter back on
-replaced what appeared to be original fuel filter
-checked for vacuum leaks

Car runs and drives great no hesitations, stuttering, no lack or loss of power.
Idles steady at 850/900rpm

Doing compression test next and cleaning all electrical connections for sensors

I have read numerous posts on numerous forums if anyone else has an idea please share!

 

[4Gwannabe]

Those things are known for CAS going bad, try testing the one currently one the engine if at all possible.

 

[KeithAZ]

As stated above the CAS is known for going bad over time, this would make sense as the CAS has to do with timing of when the spark plugs receive spark. Also would explain why you are getting multiple misfires in all cylinder's and not just one.

 

[xnol1m1tzx]

I tested the cam position sensor pigtail and it sees 5v signal wire and 8.9v constant power ..battery is 12.5
Manual doesn't give specific values for the sensor itself

 

[xnol1m1tzx]

Also under cranking the signal wire should read.4-3v and I'm seeing .39 up to 5v
This is making me think PCM issue now because it's not seeing the proper supply voltage according to Haynes I don't know if anyone has a mitsubishi mechanics manual and can verify these numbers

 

[xnol1m1tzx]

Also under cranking supply voltage fluctuates between 8.87-9.03

 

[xnol1m1tzx]

Yeah the cam position sensor as well as the crank position sensor has to do with timing/spark/injector pulse width
The problem is I have no symptoms

Anyone know if I can use an ecu from an 1995-1996 or do I need 1997-1999 mt ecu?
Local junk yard doesn't have my body style in manual only AT

 

[xnol1m1tzx]

Also I read somewhere the avenger/seabring PCM May be useable if equipped with the 420a m/t
Can anyone confirm this?

 

[Zero6391]

Did you ever figure out the problem if it was the ecu or not? im having the exact same issues