Hello , I have a 2005 on a 55reg astra 1.6 petrol twinport with a P0171 error. From time to time it hesitates when driving and judders a bit, is this because of this error I understand it is running to lean not enough petrol. Should I change the rocker cover as there is a diaphragm built into the undeside of the cover, the diaphragm could be split? Is changing the rocker cover a common fix for this problem.
Thanks for any advice.