Okay MOT today... Put the CAT back on...
Testing emissions and passed the CO2. So CAT is fine.
However they failed it on a weak Lambda signal. Saying the car was running very very weak. I asked what could be causing this and they were unsure.
On AFR gauge it shows my car isn't running weak. I got a new Lambda sensor (bosch). The Evo 6 intercooler is the new addition and I know there is a small boost leak somewhere. Would this be the cause?
I've told the garage I'll hook up the stock intercooler and try for the re-test. Just in case this is the problem.
I've had no ECU light come on either and would presume if the car was running weak it would shows itself?