Nreg subaru legacy twin turbo auto MISFIRE

Question

hi i have a subaru legacy gt twin turbo automatic and a light just came on my dashboard it looks like a pan with 4 wavey lines above it and now it chuggers on tick over like a misfire some one told me the light might be my cat light but it only came on for about 10seconds then went out and hasent come back on again but still the car is shecking any idears thanks. mathtew