Thanks for that very amusing story, it made my day. Fancy that, a car
manufacturer so disrepectful of their customers that they use low grade
electrolytic filter caps in their ECUs.

Probably the same reasoning is used to justify low quality metallurgy in
their piston rings, short lived valve stem seals, auto boxes that fail
prematurely etc.  They aren't called Mitsushitty for nothing.

As for your ECU rebooting itself, that needn't be caused by bad caps. You
might simply have a bad ground or a faulty (electrically noisy) alternator
or some other noisy high current appliance.  Unless you have electronics
knowledge, a schematic will be of no use to to you. It would be better
substitute - pull an ECU from an abandoned Stealth (there must be lots of
them in growing weeds on the side your roads).

Hope that helps

Brian,

When you changed the 4 large electrolytic capacitors, assuming they were
leaking, did you also  thoroughly clean the PCB and make sure there was no
permanent damage to any conductive paths or other nearby components?

If you did, then could you have stressed any solder connections and caused
an intermittent condition?  Failing that, a salvaged or rebuilt ECU may be
the next step.  Good luck!

 Bob