Dead cat

Given the lamda readings you can either try getting the cat very hot or a new cat, I'd try the long run 1st.

I'll second that. Worth a shot - nothing to lose except a few quid on petrol. Some years ago one of my cars failed the MOT marginally on emissions. The tester recommended I take the car for a spirited drive and get it nice and hot. I did just that, brought it straight back, he retested it right away and it passed. It passed the MOT the following year too (same cat) as I made sure I took it for a decent run before I dropped it off.

At least 10 miles, some at very high revs .. it needs to get hot .. ;)

Erm, when did it last have plugs and have you checked the actual running temperature- I know these dont have a temp gauge.... We all know Ford thermostats get lazy and open prematurely with age....

From the readings it's running slightly rich, not necessarily a problem with the catalyst....

Tim..

the cat is working as the hc is OK. Why has the engine speed not been measured? does the KA have an accurate tacho? A general service and change the thermostat would be the first things to do. Then move onto the CTS or its plug.

Bit of extra info, bought a lambda sensor and plugs from the local spares shop. Light off for a while then back on, lambda sensor fault, huge flat spot.

I belong in the carb era so booked it in, they replaced both sensors, said the one I bought had a slow response.

They left it running for an hour and the readings improved, hence give it a loooong run. MOT 28 March. Rog

leaving it running for a long time would get it running hot (which might also point to a thermostat fault.) The thermostat is very easy to get at and cheap to renew. Likewise air filter.