Hello,

My 1997 Dodge dakota club cab failed an emissions test with CO values above the limit. OBD also shows a p0441 fault code and the fuel consumption is higher than usual.

To my understanding, the engine is running rich and causing the engine to consume more fuel and the emmisions test to fail.

I've changed all the spark plugs, air filter, replaced the gas cap and the purge valve. My next guess is the catalytic converter. Is there other parts that would need to be replaced? And are there ways to trim the fuel injection manually in any way?

Thank you in advance!

 

Apparently there is a vacuum switch involved in there that can go bad as well. Those codes are always fun to diagnose....

What plugs ya have in there? How old are the O2 sensors?

 

HeyYou, thank you for your fast reply!

Yes, it has been nerve-wracking to pin-point the problem...
I replaced the old plugs with iridium spark plugs with the brand name Brisk. I do not know how old the 02 sensors are. How can I know if they are malfunctioning? And where is the vacuum switch located? And how would I diagnose it?

 

Get rid of the iridium plugs. Standard copper plugs only. These engines are notorious for not playing nice with the rare-earth fellers..... End up with mystery misfires.....