I have a 94 Dodge Dakota with a 5.2 V8. It has pace setter headers, a high flow dual exhuast. The computer is relaying trouble code 21 which is the O2 sensor. The check engine light comes on spiratically. If I shut the truck off and start it again the light will be out then come on after a few minutes. Is the O2 sensor the problem or is the exhuast popping the O2 sensor codes. What should I do to eliminate this problem. Also I am not sure if this is related but, when the truck idles for a period of time it goes into a mode where it wants to stall. What I mean is it sounds as if the truck is sucking a lot of air and wants to stall. I have a 12 inch K&N air filter that has the chrome tops and bottoms and is open around the outside.

Thx

 

THE SYMPOMS YOU DESCRIBED ARE THE EXACT SAME AS MINE. MINE STARTED SHORTLY AFTER CHANGING THE EXAUST ( COSTOM 2.5" OFF MOTOR INTO 3" WITH HIGH FLOW CAT). I'VE HEARD THAT YOU CAN BY PASS IT. BUT I'M NOT SURE HOW. IF YOU FIND ANYTHING OUT PLEASE LET ME KNOW. THANKS

 

If you guys got any anti-seize or grease on the sensor part of the o2 sensor, you may have contaminated it. If so, its best just to replace it. Also, it often helps to run a ground wire from the ground point on the rear of the passenger side head to the exhaust, as the o2 sensor uses a ground reference back to the computer for measurement.