Ok, when I bought my car a couple weeks ago, the guy had all the service records, including the recent timing belt change...
...also including a recent "tune up". He mentioned that an ignition coil had gone bad and was discovered during the tuneup, and it was replaced, but the ignition timing was not adjusted afterwards... (or something like that)... long story short, he said that he knew the ignition timing was now off after the "tune up" and that I would want to get that fixed...
So yesterday I hooked up the timing light. I had fully warmed the engine, parked on a level surface, AT in Park, and looked at the timing. It looked like it was set to 8 BTDC ... I had to fiddle with the inductive pickup on the wires to coil pack 1, and it still only flashes intermittently... Anyway, I loosened the CAS and turned it until the mark was on 15 degrees.
I read in a thread somewhere that you should put the pickup only on the "fat wire" going to the coil, so I tried that, but then I got too many flashes, including multiple timing marks about 10 degrees apart (15 and 25?) I also read that there is another wire somewhere intended for a timing light pickup, but I'm not yet sure where that is ("There is also a black loop on the PTU harness that is supposed to be used for this" - what is the PTU?)
So, anyway... I set the timing to 15, and drove around the block. Now I'm hearking knocking-n-pinging.
This has me very worried.. 
.Did I screw it up? should I put the timing back where it was? Or perhaps...I also read that the ECU makes adjustments and sometimes needs to be reset after fixes... (this article mentions resetting the ECU after adjusting TB's). Does the ECU also make adjustments if it senses the timing is wrong? maybe I should pull the battery for 30 minutes and let it "forget"? I dunno.
I will at least recheck the timing with the AT in neutral just in case that affects the timing measurement...