Thanks. Did I mention I stuck some of this Rislone 3x ZDDP Additive to the engine oil?
Shortly after that (this has been weeks by now) I started using a Biodiesel blend (Sticker at the pump says "Between 5% and 20%") and the engine sounds like it's running smoother; I'm not sure why it is though, if it's the additive or the fuel. Nifty though and I like the fuel. I also read that Biodiesel works as a solvent and will loosen unburnt fuel which (in some cases) clogs a fuel filter - though the quickest way to find out would be to use 100% if the system works that way.
Oh, I also didn't mention this earlier; there's a rust spot (really, it's all the way through) just above the tailpipe. That has to be repaired and I have the metal piece needed, thankfully.