stupid EPC light help?

[motoxpalmer]

OK so i have just put a new engine in my car turned it over fired up running like a good one then i had a water leak on the rear of the engine so i took of the pipes and took the water pump thingy (lol) on the right hand side of the engine what all the pipes go to built it all back up started stright up BUT then it cut out and EPC light came on the car wont start while the light is on the dash but when it goes off after about 8 seconds of turning the engine over starts stright up but sounds abit sluggish and loss of power any advice would be great its really doing my head in now and the 5lb lump hammer is starting to look at me lol..... cheers

[alexperkins]

Get it scanned with vagcom -youve got an electrical fault