Ford Fiesta: '98 Ghia 1.25 16v

[parkodrive]

Basically, it failed its mot. Corrosion and emissions. The Corrosion i can sort that no problem. However, the emissions is somewhat trickier as it wasn't just a little out. It was way out. Stupendously so even. As the lambda failed 0.85 and 0.87 when it should be between 0.97 & 1.03 at both fast idle tests, is this indicative of the sensor failing, or will it also be the cat?

I recently did a vac test and there was no change in the revs. Same when I checked for shorts on the ht leads. The air filter is just under a year old and has been cleaned 3 times in the 8 months I've had the car. The MAF was also cleaned about 2 months ago which solved an issue that was present at the time (loss of power at 3.5k rpm and above) so I'm pretty certain its not the intake causing such bad emissions.

I've cleaned the injectors a couple of times since owning the car (I thought they were the culprit of the above issue) so I'm guessing its not a problem there which leads me to the lambda and the cat.

The engine is producing plenty of power and revs freely (its actually a rapid little motor thats given me a few smiles on the country lanes near me) though it can feel sluggish under load at times which would tie into a faulty 02 reading from the lambda?

I've added a link with all of the values for the emissions, hopefully it will help.

https://drive.google.com/file/d/0By7pkW9WDOQTa08zS...

[Jimmyarm]

You need to see the live readings from the O2 sensors really but looking at those results I'd suspect a knackered cat with potentially a further underlying problem.

[Pumaracing]

It's abundantly obvious that with lambda readings so rich it must be the lambda sensor has failed. Can't possibly just be the cat. If the lambda sensor was ok then the fuel mixture would be stoich (14.7:1) and the MOT lambda would be normal even if the CO was a bit high due to a failed cat.