Washing Machine playing tricks?

My servis M9090 washer/dryer is playing tricks on me I think. I recently had the water pump replaced.
The machine runs through each programme setting without any bother so long as there are on items in it, but once I put clothes in, it works for a while then refuses to complete wash/rinse cycles and fast speed cycles..........very confused.........is there some sort of senor that needs seeing too. All pipes are clean, clear and not kinked.......help me!!!!