There are specific emission levels for the 3.9 Plus 8 - Lambda is 0.9 to 1.05 , idle CO is 0.5 , fast idle CO is 0.3, HC is 200
These are listed in the 'In Service Exhaust Emission Standards for Road Vehicles'
For some reason the exhaust emission analysers don't seem to pull up this data
I appreciate that you are currently outside of these limits.
As there is no MIL light on the 3.9 there could be a diagnostic error that you don't know about, may be worth getting the codes checked
As well as the MAF it could be worth checking other common items, are the lambda sensor heaters working, is the engine temperature sensor working, and is the fuel pressure correct ?
Best wishes
Mike
Last edited by teknome; 14/10/20 09:44 PM.
