I have a 6 year old automatic i30 Hyundai. Two years ago I had a problem - when driving if I took my foot off the accelerator, when going down hill, the revs would shoot up to 4000rpm until I took my foot off the accelerator and on some corners when the car was changing down it would thump into gear. The garage changed the instrument cluster panel at a cost of 1,500 euros. The car seemed OK.
Recently, I had to have a jump start because of a flat battery. The same problem has started again - when moving from a flat road down an incline the car revs up to 4000rpm or when pushing foot down on the accelerator when overtaking. Twice it has thumped into gear on a bend.
Does anyone know what might be causing this? The garage here in Portugal seem to have difficulty diagnosing things.