I have deleted the secondary air system on mine years who so I know it's not related to that.

I have just heard back from the Subaru garage. They said (as requested by me) they changed the exhaust air flow sensors. Firstly the post cat one which made no difference and then the pre-cat one (the one I asked to change) and low and behold it passed the emissions test and MOT. Sorted!

Seems it was the sensor after all as I had thought. However he did say it had given erratic readings so he suspected the cat was on its way out. Will see next year.

So sorted. Phew!

Thanks for all the advice peeps. I will try some cat cleaner too.

 

have supplied quite a few Cobra systems & cats and they are good quality IMO and never had any emissions issues

 

Very good to know thank you.

To say I'm relieved they have now proved the air flow sensor was at fault is an understatement. They are still worried as the readings jumped about initially. But we'll see how I get on in next years MOT.

Thanks for the vote of confidence and all the replies all.

 

Yep my Cobrasport sportscat downpipe split after 40,000 easy miles. I sent it back asking for a replacement and they did a Frankenstein and welded it up claiming it was better than new. I wasn't happy.

After less than another 1,000 miles the downpipe split again - this time lower down and then blew apart directly under the cat. I knew I didn't want another piece of crap so went and bought a proper one from Hayward & Scott. Twice the money, much better flow and a bit more power. Lesson learnt.

A