So im not new to the group. I have researched this problem and cant find an answer. I have a 95 s10 blazer. I have replaced the plugs,wires,egr,cap and rotor, and now cat,02 sensors and exhaust. Car started up and ran like a brand new vehicle but after 10 minutes of running the new cat started to glow red and the car started to bog down and run like crap. I have tested the fuel system, and it running right where it should be. Any assistance would be great.

 

U got a cat...... Plain and simple

 

What brand of O2 sensors did you use? Perhaps the PCM/ECM is not reading the new O2 sensors correctly.

Try removing the O2 sensor from the exhaust system, leave it electrically connected and see if the engine runs better after 10 min or so. This will set the Check Engine Lite as the PCM/ECM will not see any change in the O2 sensor readings...so sets an error.

But if the engine runs fine, then possible the new O2 sensor is faulty.