i have a 2005 1.8 Vectra Exclusive with approx 53000 on the clock, always been serviced as scheduled.
Timing bet has not been changed yet as not due til 60000.

its now developed a misfire at approx 1500 revs, making it lumpy until it passes 2200 revs. then the engine runs fine, until the revs drop down to 1500 or below again.

no idea why but its irritating as anything.

any help or suggestions very welcome....