Too high iddle CO emissions

[Njaah]

Hi everyone
My Puma (1.7 1998) recently failed at annual inspection (MOT in UK?) due to CO emissions being too high on idle. If I remember correctly, it was somewhere around 1.7 where the limit is 0.5. Interestingly that was the only reading to fail, and on revs CO readings are also fine (0.3). The guy doing the test said it's probably some of the sensor but didn't specify.

I'm wondering what this could be? Been thinking about oxygen sensor, as it's pretty easy to replace but decided to ask here first!

Cheers!

 

[RoadWarrior]

There's two oxygen sensors on a 1999 and up Puma. They usually throw up codes when they're bad enough to fail emissions. Take it for MOT after a long drive. Give it a bit of a hoon to clear it out. I do this on diesels before MOT. Get it scanned before wasti g money on sensors on a whim.

 

[Wild E. Coyote]

And when you try actually undoing any of them you may want to rethink about the formulation 'as it's pretty easy to replace'... :wink: