problem with engine light and misfire on 2001 Saab 9-5

i was wondering if someone can help me resolve this issue i washed the motor on my saab know it has a misfire and the engine light comes on changed the spark plugs but it doing the same thing and was wondering if it could be the baccum hose cause the one it had was remended with black tape i replaced it but dont think its working so can any one help me asp thanks.

Asked by for the 2001 Saab 9-5