I bought a 05 lariat supercrew 4x4 1.5 years ago and had to repalce the cat when it was bought and was warrantied and now its bad again. I am trying to figure out why it is doing this. It was stock truck when they went bad. NO CEL on anything it just rattles inside like crazy same signs on both. I now have a gryphon with custom 87 perf tune but want to make sure when I put the maggie high flows on it dosnt ruin them. Any help is much appreciated.
Thanks
Dave

 

^ Ya could just run none and be done with it! But... that is a band-aid and your fixing the problem. It sounds to me like you have some wrong here. Fuel mixture must be off for some reason.

 

Well talkedwith bill today at PHP he thinks with no code popping its just a bad cat from the start. So its tim for high flows now.

 

my driver side rear rattles a lot too and i can smell exhaust gasses on startup.

i assume its going to need to be replace too? does anyone know if it'll pass the sniffer test still?

 

They will all smell on a cold start up. The catalyst only works when it is hot.

 

just check to be certain that your o2 sensors are working correctly before throwin parts at it. a quick scan will tell you if they are or not.

 

whats the easiest way to test the o2 sensors?

 

^ scan

 

Well gotta love my dealership!!! Took it in and had a complete check on injectors O2 sensors and fuel trims...... well I set back to stock from the gryphon before they got it and it hadnt releaned some stuff but they said everything was good so I guess faulty cat. Well the best part the sales manager(a very good friend) said what are you doing told him he said we will cover a new one I said its out of warranty he said they will take care of me and the replacement will be done at the best exhaust shop around they are going to put a magnaflow replacement he said it will be good for my GVWR of 6300lbs I will see what they put on it tomorrow and let ya all know.
Dave