Problem with emissionvalues.

[holmbergoo]

Hi. Bought a boxster last year but have not used it anything. I bought it from GB but I can't register it in Sweden because of the high emission values. Porsche center had it fixed last week and replaced the oxygen sensors but when I tested the car, the high emission values remained. Yesterday when I used piwis and read the codes, it said:
misfire, emission related for cylinder One to three. Please help.