Hi Everyone,

I just had my cat converter with a high flow Catco. They told me to tune the car up right after. I did so, replaced the platinum's with AC Delco Iridium and a new set of spark plug wires. The car had these aluminum ends like to keep the plug wires from touching things?

That is it. Now 14 miles 10 free way is using a half quarter tank of gas. roughly 2 gallons..............this is out of control! I did however a month prior have a stock muffler with a two outlet. I did notice the old cat was constricted as now that little muffler is louder than in the past. I cannot figure out why it is sucking so much gas. It does not smell of it, seems slightly more sluggish and perhaps not as smooth but not much. I also put some lucas fuel inj. cleaner in the gas tank and that didn't help either.

Someone said the sensor by the cat could be bad. I don't have a check engine light on. I just had it smogged and passed without codes.

So I though I would ask all of you.................
3.8, 6 cyl. 2000 Camaro Automatic

 

The gas gages in these car are horrible, I would not trust them. You should use the fill it then go back to the same pump and fill it again and use your trip meter to track it.

It is recommended anytime you have a plugged Cat that you replace the O2 sensors between the engine and the Cat. For you that means both manifold O2 sensor.

Just about any sensor can cause bad mileage but your O2 sensors are watching for problems. They are sort of the police watching to see if ever thing else is working. When they go bad you can really have bad mileage.

 

Thank you so much for your reply, I will replace the sensors and definitely watch the tank for accuracy as you suggested.

 

did you ever solve your problem?