Dale R wrote:
 I do electronic troubleshooting for a living. Usually,
when I have repeated failures of a single module it's
because something else to which it is connected is "eating"
it. A likely candidate is a sensor that has too low
impedence/resistence and therefore is passing too much
current. Less common in recent years is voltage on the
return line.  It's amazing how dead a component will get
with as little as -1.5V on a line that's supposed to be
zero.
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Amen to what Dale says here John. Tracy replaced 4 chips(A&B twice)
before we fiqured out that there apparently was a bad DPDT switch on one
of the injector disable switches that was leaking voltage back thru a 5
volt computer signal. We never proved this, but when the double fuel flow
line on these switches was eliminated in favor of a single pole simple
switch it has cured the problem todate.

Bernie