please give advice 2003 s60
 

I had codes pulled I was told it was the catalytic converter, downstream O2 sensor, and map sensor. Replaced the catalytic converter and clean sensors, took off negative on battery and engine light went off but returned saying code 3 misfire on 4th cylinder. Replaced all five spark plugs and now the car says try sift up or slown down in my message*box*and check engine light flashes. I can get RPM to 3000 but speed to 20 mph, once I make a complete stop car barely wants to move and rattles or knocks. Great on gas but lately guzzling it so fast. What should I change or fix or what should I do.

Do you have any P0xxx codes?

Already been solved. The coils were bad.