Alright i have decided to cut the rear cats off my truck but sadly i am nowere near my truck. I can get the pipe i need cheaper were i am now. My question is how long of a piece of pipe do i need to replace both rear cats.

 

don't do it your motor will slowly break and your gas mileage will go down. I cut my muffler off and now I get bad gas mileage.

 

how will the engine break?

 

it affects the o2 sensors which will tell your computer to run lean. My 98 runs lean due to no muffler. it will slowly mess up your motor.

 

Both statements are EXTREMELY false.

Cutting off the rear cats will not effect the cars performance in any negative way. The only way to mess up the vehicles o2 reading is to change the distance of the front o2s from stock position(long tube headers). The only thing rear o2s do is measure the exhaust for cat operation. They in NO way influence the fuel mapping of the vehicle. The only thing you will need to do is turn your rear o2 sensors off in a tune or get MIL eliminators, only to turn the CEL off. The CEL only comes on to alert you that your cats are not working and need to be replaced.

Removing a muffler will in no way hurt or hinder any operation of the fuel mapping or performance of the motor. Something else is wrong with your truck.

I have been running no cats on my mustang for years. As much as I beat on it, by your statements, my car should be dead in the water.

Again, unless you change the distance of the FRONT 02s with some long tube headers, you will not mess anything up. Its impossible. The only 02 sensors that have any link to the fuel mapping of the truck are the front. The rears only measure the functionality of your cats. And as long as you only cut 2/4 off, you will not even throw a code for it.

 

I guess its time for a new mechanic I dont know sh*t when it comes to new trucks lol.

and while we are talking about fuel the guy who read the code told me this is why it ran lean does it have to do with anything?

 

You will find that most "mechanics" know nothing about how a modern EEC-V system works, or any computer system for that matter. Basically the only things you can do to your modern Ford(up until 2004 when they went to the Spanish Oak computer) that will effect the fuel mapping is changing the MAF location to a less optimal condition, putting on long tubes without getting a tune, or changing things like injector size without letting the PCM know. Basically, anything you do past the front 02 sensors is ok short of just running open headers. Thats not the smartest thing to do with a stock valvetrain motor.

The computer can correct for a LOT, but those few things it just cant handle.

Without seeing the code I cant really tell you much. My guess is if you had a bank 1/2 lean code you need to change out one of your front o2 sensors. Thats a common code for that situation. 9/10x thats the fix for it.

 

It had 2 lean codes and does autozone do the check engine lights still?

 

Yea, vatozone does em, along with pretty much every other parts store.

 

Lovefx you should buy 4ft of pipe to have plenty extra, good luck