I have a very random misfire, it's pretty un-repeatable, it occurs 90% of the time during cruise, but can happen at any time.
see the attached pic from a datalog, (I can attach that if anyone wants it?)
you can see that the revs hold steady as does TPS and MAP, but where you can see the AFR fluctuate I have a miss fire, it's almost like the car doesn't fire on one cylinder. It's extremely annoying, especially now my daily commute now involves lots of steady state cruising :-(
I've got a set of Mazdaspeed Ignition leads and tried swopping them for another set with no joy (neither set are new however...) I've also tried new plugs, (NGK-R's and Iridiums) to no avail.
I'l literally at the end of my tether at the moment, long hours and a stressful drive does not make me enjoy my car!
Any and all advice is much appreciated!