Black Smoke, Extremely Bad Running and Excessive Fuel Use

I've been running an 1993 NA which has suddenly started idling like a dragster and driving like a kangaroo. All whilst belching clouds of Black smoke and using a lot of petrol.

Just changed all six plugs, which were old and worn - but more importantly extremely sooty.

Car will not idle very well off choke, frequently cuts out and 'kangaroos' with erratic power delivery.

Going through the archives it looks as though it may be a Lambda sensor or two that have gone. Could anyone confirm that that's a possible, or better yet, likely issue?

I'd love a little expertise to save me chucking more cash at wrong solutions.

Any help greatly appreciated.

Highly likely it could be the lambda sensor - either worth a clean (instructions on here) or look at a new one.

Did this happen overnight or has it happened over a period of time? If it's overnight it's very unlikely to be a lambda issue as with the NA there are two of them and a sudden failure of both is unlikely at best. Check for split/popped off vacuum lines and make sure you run a check for error codes (click the highlighted text)

Originally I had a deadish spot at constant throttle for maybe two or three days. Then suddenly went from grumpy to terminal. Have had all the lines on ant off - most seem to be airtightish, and removing those downstream of the throttle only improves running. Will try the ECU codes tomorrow, cheers!