Sorry to necro this thread, but I wanted to let everyone who followed this originally know: I'm back!
I ended up selling the car back to the guy I bought it from at the end of 2015 and it ran fine for him until it didn't. He never bothered diagnosing or fixing the problem, so we don't know if it was oil related but he said he doesn't think it was. He was well aware of the canola experiment, and the fact that it had canola in the crankcase when he bought it; AFAIK he continued running that blend, as well, because he noted a major improvement in idle smoothness and throttle responsiveness from when he had owned it before.
He was my roommate when I bought it, for most of the time that I owned it, and again when I sold it back to him. He was well aware of the maintenance history of the vehicle while I owned it, and nothing I did while it was mine would have accounted for the change he noticed -- except for the oil.
That said, the experiment is *NOT* over!! Once I have the fuel trim issue with my 97 Ranger sorted out I'm doing one more OCI with Motorcraft 5w30, then continuing the experiment with this engine starting at 25% canola for 3k.
Unlike the Corolla, this engine burns *NO* oil, so who knows WHAT we might see. I do have plans to rebuild this engine at some point (actually, the whole truck -- I bought it as a project vehicle, but buying a house is more important right now -- need somewhere to actually do the work).
Stay tuned for a new canola thread in a couple months or so.