Recently my 240`s Lambda warning light came up- I continued to use the car, 3 days later it began missfiring in low revs, a couple days after refused to start from cold. My mechanic changed plugs leads and distributer cap/rotor, when I got it back the Lambda light was out and the car ran fine.
The Lambda light then came back on after a couple days, and the problem repeated itself, exactly the same pattern.
This has now happened 4 times, the mechanic seems to be at a loss.
At some stage in the proceedings I have also tried a known good HT coil, no joy there either.
Any ideas anyone?

 

I believe the Lambda light has to do with the Oxygen sensor. It's located under the exhaust manifold or exhaust header pipe (can't quite remember which at the moment).