no power on 1995 BMW 318ti

i changed the plugs and lost all kind of power idle a lil rough but not to bad cant get over 50mph no power goin up hill or startin off did everythin to my knowlegde cant figure it out

1 answer
Sounds like the problem I had with my 1998 318ti. Most likely your catalytic converter is clogged, BMW had a recall on the catalytic converters on the 318's they are known to go bad.