Posted by Peter Wright on April 23, 2004, 10:02 am, in reply to "FIX"
Nice fix Eamonn.
I presume you measured AFTER the cat?
If you had been able to read CO corr or CO var then you would have picked the exhaust leak. Was it before or after the cat??
CO% of 0.7% before the cat is pretty normal. I regularly see 0.5 to 1.5% I don't see this as lean.
The reason for the, "what appears lower than normal HC for this condition is the action of the cat". This would also pull a CO reading of eg. 1.5 down to 0.7%
An intermittent misfire will have less an effect than a constant misfire.
If you have any further questions, don't hesitate to contact me.
I have a chart for exhaust gas emission problems pre cat.