cot?? cat over temp yes its disabled

 

Best answer now is a wideband and if it's under 13 to 1 AFR turn some or most of the kr off. You will hear any knock bad enough to damage the engine.

 

my stock O2's are hitting between 855 and 900 on the data log but at about 100mph is where it starts.

 

The stok o2's should be closer to 880, not going below 870 much at all, and absolutely not any further than 860.

The higher load and sustaining the higher rpms will cause it to go slightly leaner. I would richen it up a little and see if it goes away.

 

hey 12sec5.3, if you have the stock injectors in a 99 you have 19#ers my friend. Even smaller than you thought Thats why their maxing out with your mods, mine are too, but for the moment I have to live with em (gotta pay for my wideband first)

 

COT enabled will not make it any leaner. It could make it richer in the closed loop Command A/F ratio. in open loop the ECM takes what ever is richest , cot a/f or PE a/f. more fuel = cooler cats

 

I'm currently using the injectors that came with the 6.0 HO. But I hear they are 24lbs also.