i have an automatic vauxhall corsa p reg and for some reason when i pull away it does not pull away in first gear it pulls away in third a mechanic said it might be the gear box selecter that has gone but since this has happened i have no reverse lights or speedometer so how do i fix this
I would check all the fuses. Sounds to me that the vehicle is in "limp" mode.
Once you find a blown fuse, you will need to work out what caused it to blow. A good auto elctrician should be able to work it out!