i read some where u can delete rear 02's. i have a 99 gmc 2500 with factory duals. it has a 6.0l

 

Welcome to the forum.

To delete O2S you need a tuner to do that.

 

Correct, you need tuning software to delete rear 02's. I deleted my rear 02 sensors using HP tuners. Click on "Engine Diag" then "DTC's". Under "SES Enable" uncheck the box and set "Error Mode" to "3-No Error Reported" for the following codes:

P0036
P0054
P0056
P0060

P0137
P0138
P0140
P0141
P0147

P0157
P0158
P0160
P0161
P0167

P2A01
P2A04

Hope this helps

 

what is a hp tuner? where can i get one.

 

You can get oxygen sensor simulator that will trick your computer into thinking that your cats are still hooked up. But I would just have one of our site sponsors tune your truck. They can delete the cats out of the program and you will get some extra horse power at the same time.