i was gonna say a vac leak! lol

lad at work has a 2.0l 306 cab and that was revving all over the place. tried 2x iscvs on it, as the first one he got was wrong lol.
that made no difference and was a bit of a head scratcher.

we rear somewhere on the net to unplug the batt for 30 seconds, its been fine since on the original iscv!

cars do odd things somethings...!

at least you found it tho!