i forgot to add -- the misfire only happens between 2000 and 3000 rpm. if i endure the misfires and put the pedal to the metal, the misfires eventually disappear as the engine winds up.

i've already changed the fuel filter. the fuel pump used to be intermittent, but after re-wiring it seems ok now (although the impeller could be damaged.. doesn't explain why the misfire disappears above 3000rpm).

the guys on the mazda626uk list are also starting to lean toward a faulty computer box. i'll try pulling the codes to see what i can get. how much does a computer box go for? mazda's aren't that common, much less a 626. will third-party ECU's work?