It has just clocked 100,000miles but has full service history and has Never had any problem worth talking about,but it has developed this problem.Sometimes when i select Park the P on the dash goes off when i let go of the gearstick,the car will then move as if in neutral,if i give the stick a hard tap forward the P comes back on although the stick doesn't seem to move any further forward.It also does the same Sometimes when i select drive,the D on the dash goes off and the car will rev freely,tap the stick back hard and it comes back on and drive is restored even though the stick doesn't really move any further back.I really like this car but as its as old as it is I dont want to spend a fortune by handing it to a dealer to be told it needs a new gearbox if it doesn't.Any suggestions to the cause would be greatly appreciated,thanks.