high emissions

Just had my P38 4.6 hse MOT'd and it failed on high emissions[only put into the test to satisfy tree hugging tits]I would welcome any ideas to lower it for the retest,dont know wether it's the lamda's or the cat i've added cat cleaner to the petrol and been advised to have a jet wash shoved up the exhaust,but I find this a bit extreme, unless you know otherwise.Couldn't get the emissions print out cos the prick aborted the test.Thanks

He would have aborted it as the figures would have been away up at about 12% or higher. I had this last MOT but one. It was one of the Lamdas. You can either change them both or if it's plugged in to Testbook for example it'll tell you which one if it's just the one that's away. I stuck on a second hand one that cost about a tenner.

Sticking a power washer up the exhaust is not recommended. Firstly because it wouldn't work and secondly even if it did it has to pass through silencers on the way to the cats so by the time it got anywhere near the front the pressure would be all but gone.

watEr in the exhaust would be bad, wouldnt wanna start it up with water could cause some damage