Thanks for the input guys. Fuzzy it happens after I've driven for a while so the car is warm. The car is absolutely fine when driving. The short term fuel trim is as would be expected constantly adding fuel and holding it back. So a lean and then rich combo.
Only when I come to a complete stop the idle goes high, the needle bounces all over the place and the short term fuel trim increases to +25% and then decreases after a short while to -25% before returning to around zero. One thing I have noted is that when this occurs the voltage of the 2nd lambda stays completely still and doesn't fluctuate the voltage until the fuel trim has returned to normal or if I race the engine a few times above 2000rpm.
I'm suspecting that there is extra air in the exhaust around the 2nd lambda but can't be sure. Do you think I'm right frank or am I barking up the wrong tree?
