My car has been throwing a code 43 for a while now. However, it only throws it when I drive a consistent speed of 50 or more and when it does throw it, the car runs better. If I'm experiencing drivability issues (bogging/power loss) that seem to get better when the CEL comes on, is it more likely my o2 sensor that's at fault or is it more fuel system related? I know code 43 is the infamous code that no one can diagnose but any insight helps. Thanks.

 

old 43. I have fixed many 43s with 02 sensors, If your 02 is aged it would be a good deal to replace it anyway. 02 senosrs can become what is known as "lazy".

 

I've had that code come from a loose connector from the O2 sensor.

 

Ok so you guys are putting your money on the o2 sensor as well? Could it be the cause for my sudden power loss? I mean, I haven't checked on a dyno to see if I'm actually not making as much power as before but just by feeling of it and a few races, it doesn't pull as hard as it did not too long ago.