Yesterday i replaced my 3 inch decat exhaust system on my 55 plate wrx with the standard system to pass an MOT

The car passed however when i put the decat system back on the power is nowhere to be found.

It had 320bhp but now has what it seems like 100bhp HELP!!! There is no real kick from the boost and 0-60 must be near 8-9secs


anyway i can get the car running properly again?

 

Reset the ECU.

The smart ECU has possibly learned to run with the cat back on. It may come back after a few drives and the ECU re-adjusts itself to the decat again

 

Or it could be completely unrelated and something else has actually failed

 

Hopefully it will come back! Will removing the battery for a while make any differance you think?

 

Not normally, the car has an ECU that will retain it's memory in the event of a loss of charge, whereas older cars would have reset once any residual charge had dissapated. A dealer will charge about £40 to scan the ECU, and if there is anything else wrong they should be able to identify it. Alternatively go to a recommended independant subaru specialist and you'll usually get a better service and they are more likely to identify your problem in my experience.