Washed the car this afternoon, turned it on to take it out for a quick drive to dry the brakes off, initially the car over-reved but blipped the throttle and it settled back down. Out on the road and after 400 yds the speedo (not revs) starts dropping to 0 then back up then down again. Did this a few times, but no affect on the driving. Out onto the main road and gave it some beans and all settled down.
Any ideas?
Cheers