159 2.2 Branches, DeCat and issues
Recently had a full aftermarket exhaust installed - mainly just a difference in the sound with no real performance gains.
Then decided to have aftermarket branches installed and decat. The 159 is not a particularly common car here so the exhaust guys had never done branches for it before, meaning mine was the research and development car.
Anyway, branches in, cats out (minicats fitted) and the engine warning light comes on. Off to Alfa and they replace spark plugs and coil pack. Light off, car runs fine for a day then light is back on.
Picking up ignition faults and some error about lambda inversion...
The alfa mechanic suggests that the exhaust guys pull the 2 rear lambdas a little out of the exhaust by adding spacers. This gets done and then back to Alfa to clear the fault codes.
Alfa fits new plugs again and clears all codes today. Within 5 minutes the light is on again and ignition faults reported. So, they are going to stick a new coil pack in (again) once they get stock.
They think the branches and decat may be screwing around with the lambda readings getting the car to burn too lean and that this is causing the plugs and coils to fail.
Does anyone here have any experiences with branches and decat on a 159?