I installed my test pipe with CEl fix and my mpg is going down. I'm just wondering is the pre-cat o2 sensor switching too fast that's why it consuming more fuel. Plus my post cat 02 sensor is switching slow but reading high voltage. I have a base knowledge of engine performance and i just want to make sure that I'm right. So give me some feed back so i can make sure. Please and thank you.

 

the primary o2 cant switch too fast slow fluctuation is a sign of a bad sensor

the secondary 02 isnt in any way responsible for fuel correction it pretty much says "yup cap is ok" or "cat isnt working efficiently enough"

bad mpg is coming from you hammering on it because the car sounds a little better now if everything else is still working correctly.

 

what type of CEL fix did you use...2006 yes?

 

Well i hooked up a snap-on solus to my car and checked the o2 sensor reading and everything is working fine. And yes some time that right foot gets a little heavy. lol

 

i use a blox CEL eliminator and that still throw a code up. so i got a spark plug fouler from autozone and stack it with the blox CEL eliminator.
so ever sense then never throw it again.

 

Foot mod needed lol