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I was using a digital voltmeter, and the reading spiked and stayed up.


Well, to me that sounds like a bad ECM. That's supposed to be the first indicator of trouble - if you're not getting the a-okay signal from the unit (continuous long sweeps, or in your case with the digital unit, repeated rise and fall readings) then I would think it is safe to say that the computer is toast. Just my 2ó...