ok i had my cat gutted a couple of months ago and at first my truck ran better but now to runs like crap is gutting the cat bad will it mess up the sensors the dealership said they will replace it for free (dealership mechanic is a buddy so hes not gunna say anythig bout it bieng gutted) will this help or will it make it worse thanks everyone

 

I dont know but all i know is my cat. melted on me and he said that the check engine light will come on if i cut it off.... so i put a new one on and it ran way better thatn before...

 

i think there is this O2 simulator that you need to buy to make the truck run right again.

 

If you gut the cat it takes all the bottom end torque away

 

Gutting the cat doesn't take the low end away, an exhaust that flows too free does. Your engine needs backpresure to keep that low end power, so if you have the factory exhaust after that you should be fine, or even an after market muffler, but if your running it straight back through the cutted cat, then yes you will loose alot of power probably.

To the point though You probably need an O2 sim so the post cat O2 sensor will send the right signal to the PCM

 

i do have a flowmaster 40 series 1 in, 2 out, dumped but i dont have any low end power could this be because of the cat.

 

If it dumps right after the muffler it could be. Whats te diameter or the piping going in?

 

The downstream O2 sensor only measures the functionality of the cat.
It does not determine fueling or spark timing - that is solely up to the upstream cat.

How did you 'gut' your converter?
If you used a steel bar and just forced it through to knock stuff out....
More than likely pieces are left in it, clogging remaining passages inside.

 

it comes mabye an inch out of the muffler and dumps i think its 2.50 in and 2 3.00 out does this sound right no i took it somewhere to get it gutted they cut a long strip off the top of the cat cleaned it out then put it back on

 

been there done that...even with muffler not enough backpressure for torque.Mabee with a differnt cam profile but not stock