The check engine light comes on with the ignition, so the bulb works. It doesn't come on running or when jumping the diagnostic plug. I think there is a Service Engine Soon light, that shows with key is on, goes out with engine running, and does not flash with the plug jumped.

I drove it and it seemed ok in running. The tailpipes are black. Either it isn't being driven much or fast, or it is dumping a lot of gas. If I remember right, a bad O2 sensor will make the injection run too much fuel on a TBI. I would think that on the TPI the same problem happens. So if you had a customer complaining about bad gas mileage and you had black tailpipes, I would think you would check all that affects excessive fuel delivery.

When I smashed down on it, the engine ran up to over 5500 and began to buck and cut out, like it hit a limiter. Since it was an automatic, I'm surprised it didn't just upshift.

Oil pressure ran about 35 cold, 20 hot idle, and about 25-30 running hot. Water temp was roughly 160.