Ben,
yup - we use the good stuff, or at least as good as we can find in San Diego. I've noticed with my MR2 that some gas stations' regular upsets that motor, but it doesn't sem to matter where we fill the Merc up at, it still rattles away when it's hot'n'bothered. Timing's dead nuts-on - had the timing light on it myself (I used to work on cars......). I'm beginning to wonder if it could be worth cleaning / flushing out the cooling system. I noticed a couple of blocked waterways on my MR2's head when it blew it's head gasket - ever been known to happen on these motors ? Sounds desperate I know, but ..........
Thanks for the reply.
Simon.