Hi BB,

Just to add to your reply..

The keyword here is "selected". The OE are selected parts from the manufacturer (I could only guess the criteria of selection). The OEM are just (unselected) parts made by same manufacturer or panel of manufacturers. The aftermarket are parts made by non-OEM manufactures thats supposed to have same specification.

In my hi-fi hobby I used to own budget Marantz products which sounds nice with average criteria of internal component selection. Then I upgraded to Naim Audio which practices in-house component testing and matching before selection. It sounded much better with music flows out like water. Equipment prices are already prohibitive with this selection method. I've yet to own an Audio Research or Krell with their esoteric component selection with out of this world pricing. So I'd imagine for OE parts something like this is being practiced.

In case of aging ECU filter caps the deterioration is more likely gradual than sudden. A car with aging ECU should be able to start no problem but when driving is involved thats when the symptoms appear. The filter caps unable to supply the filtering needed when ECU activity becomes more demanding (all computer microchips inside starts to demand more power) ie driving. Early symptoms could appear as intermittent misfire, escalating to complete shutdown.

You'll suspect its the ECU fault when you have taken good care with all parts replacement. You'll know its the ECU fault when its replaced with a good known part.

Hope that helps,
Amarin