For a few years, my 2003 Zetec Fiesta has made a fairly annoying rattling noise under acceleration. It sounds like knocking (or pinking, I was never sure if there's a difference) to me, but I thought they didn't do that anymore. Unless something in the PCM is wrong? I don't see any codes displayed. It doesn't always do it, but you can generally provoke it, even at something like 3000RPM, which I'd have previously thought was too high for knocking (given the usual causes in the good ole days).
Or is it just something rattling? I know it's hard for anyone to say, without actually hearing it, but if it is knocking, what might I look for?