I've got (and probably had for some time) a slight misfire under no-load conditions around 2500-3000 rpm. Identified during my recent MoT when they do the fast idle emissions check. But - after a while it disappears with a slight change of rpm as if some switch or valve is cutting in/out.
I've swapped the DI unit for my spare - no difference.
Also I use a "new" set of plugs for the test.
It is not noticeable during driving the car - never has been.
Any clues as to what it might be?
Thanks
Dave
