Had the NCT today and passed everything bar the emissions.Failed on CO on both low and high idle.Passed lambda and HC.The car has a lot of performance mods and a simtec ecu.
For the nct i fitted a used cat which im told is perfect,new genuine subaru center section and a used sti back box,all with new subaru gaskets.
With this result what be the best thing to try next,diptane,cat or lambda?
The reading are as follows

For the nct i fitted a used cat which im told is perfect,new genuine subaru center section and a used sti back box,all with new subaru gaskets.
With this result what be the best thing to try next,diptane,cat or lambda?
The reading are as follows
