Here's the reason I want a wiring harness. The thing sparks irregular. It will spark anywhere from once to 8 times successively, then sit out a turn or two, then resume for another random amount of times. I'd decided it was a wiring issue. I have a couple of possibilities in the wings for a replacement harness after inquiring today. But, I figured, "Well, if I'm going to (potentially) replace my old harness, why dont' I go pull it(the Opti and ICM wires) out of the split loom and see if anything looks amiss?". So I just walked back from the garage having done that. Here's what I found. The ICM wire is completely pulled out of the loom. The wire now goes straight from the PCM to the LTCC box. I tried the opti test (spinning it by hand, watching the LTCC diagnostic LED's (still flashing 3 times, indicating poor signal) and the plugs (still firing indiscriminantly). So I started pulling the Opti connectors wires out of the loom. First wire, okay(5volts). Second wire, okay(5volts). Third wire, okay(12volts). Fourth wire... interesting. This is a pink wire but about halfway to the PCM, it "Y"s into two pinks. One leads to the PCM, the other one darts down into a smaller loom and... is cut/broken/disconnected ?????! Now according to the book and web references, this connection at the opti is like a ground? But in the pictures, it's shown with an asterisk beside it. Of course, the picture, having been snipped from a book or manual, doesn't have the legend saying what the asterisk implies. I'm going searching now to see if I can find something definite about it.