Okay, now this is getting WAY, WAY too weird for me, and I'm really freaking out. Especially as I'm renting a car until I get the Volvo fixed and can't afford to keep that up for too long.

The latest:
It started and ran, kind of crappy, etc. While it was running I decided to look the error codes on the diagnostic gadget. The one that had the LED stuck "on" before. When I plugged the jumper into socket #2, the engine smoothed out, and the LED flashed on just as I plugged in, then went out. I was able to check the error codes, and got a 1-3-1, which is "ignition system signal missing on starting." I'll worry about that later. Checked the #6 socket too, for the igniton computer, got a 1-4-4, "No load signal from fuel injection unit," which turns on the "check engine" light! But the point is that now I was able to scan for codes, then actually reset them for the LH Fuel Injection Computer. After resetting them, I gave it some throttle, and to my surprise it revved up. BUT, the "Check Engine" light was on the whole time. Did this a couple of times before I noticed a cloud of BLUE SMOKE behind me. Awww S_ _ _!

She was also pouring oil out all over the place. From the front seals, and the rear main seal. Tons of it. Yet there was more oil on the dipstick than there should have been. I am figuring that the "excess" oil was actuall gas that was dumped in the cylinders when the computer was going mental, and the lower viscosity and higher fill level accounts for the problem.

Was able to start it up again, and same results, but this time without the blue smoke. Oil level is still way too high, so will drain and refill with new this evening to get rid of the gassy, thinned stuff.

But, in the meanwhile, the computer seems to be going nuts again. And the diagnostic connector is kind of intermittant. God, what is the matter with this frigging car? I'm really getting into a panic here. The more I chase down the problem, the crazier and more elusive it gets. Unless it is the computer and the oil problem is just from the super excess gas in the cylinders washing past the rings and into the crankcase.

To this point I have checked everything that seems logical; the AMM, the coolant temp sensor, the diagnostic codes, the hoses, the intake ducts, etc. To some, intermittant success, but nothing definative yet. And the problem with the sudden bleeding oil all over really scares me. Could the whole thing be mechanical and not electrical? Like a shot piston ring or something?