Tc and abs lights on?

i'm driving a 1999 vectra on a t reg first i had an engine light on so i replaced the lambda sensor and that solved that but now iv got my tc and my abs light on but only comes on after i've been driving it for about 1 hour plus it keeps stalling and the speedo stops working? it's been on a diognosis machine but won't connect then i've been told it's had another engine put in so can anyone please advise me wat it is or could be xxxxxxx