Hi, I am now to the owners club and I am after some advice, my 2000 turbo failed it's MOT on its idle emissions but passed on everything else no problem. Can anyone shed any light on the cause? 

Welcome to the club!

Is the exhaust modified? Still have all the cats in place?

It's completely standard with 80k on the clock mate

My guess is either the cat is not working anymore or your lambda sensor isn't working. I take it you have no engine warning lights?

No there's no warning lights on, the cat is coming up 17 years old so it could be that, it just baffled me because it passed the other emissions tests. 

Could be something else going on then if it's only the idle emissions. How is your air filter looking?

I'd still have the codes read we have a guide on here on how to read them yourself. CLICK HERE 

I'd almost put money on 02 sensor or a sensor I wonder if the ECU bulbs been removed to painted over. Could be wrong but that would be my first guess or the cats on it's way out. Only other thing you could do is see if anyone local will tell you about a friendly mot tester that doesn't mind passing decated car's 

I will check the air filter and put some new plugs in, I've got a list to do over winter.. I need a new exhaust I think but to keep it standard off Subaru would be nearly £800.. And that's just for cat back! I think not. I want a stainless system that looks like the original with twin tail pipes, I can't find anything suitable as its all massive slash pipes, any ideas would be appreciated. I got it passed with a mix and match but it bothers me that there's still a problem. 

Take a look here mate they do some good stuff 

http://www.haywardandscott.com/subaru/impreza-classic.html

Cheers mate, I'll get a look at the codes asap. Cheers. 

Had this exact problem on same car in mates garage, turned out to be o2 sensor in this case

Cheers. I am getting an exhaust made at V R Racing in Kendal they are making it how I want so I'll put a new sensor in then.