cel on when running 70 plus

[X-1]

I have asked this before, but now it has a new twist. Before when I ran 70 plus for over an hour the cel would come on, but ex still ran fine, after slowing down, or turning the ex off it would go away, now that my ex is lifted with the 33's I still get the cel when running over 70 for a long period of time. With the bigger tires the rpm's have dropped around 500 from 2800 to about 22-2300 at 70 miles per hour, it has a new speed sensor also, so what now, maintance wise it is all new, it's not rpm related, the only common thing is wheel speed.

 

[jimbo74]

if the car is warmed up at that point (probably) it wouls seem if the 02 sensors are bad and triggering it.....

 

[aldive]

You really need to scan for the code.

 

[Rhett]

Sounds like O2s to me too. Mine did that with bad O2s. It took the O2s a while to go out; at first it did CEL on the highway speed. Then eventually it got to where the CEL came on in town driving. Then the truck died while driving. At this point I changed O2s and no problems since.

 

[B94Sport]

I also think it is a bad O2 sensor. I had the exact same situation, resulting from a failed FPR that was dumping fuel into the engine and fouling up the exhaust. But if you are getting better fuel economy than I was at that time (12 MPG on the highway), I would say it's just an O2 sensor.