I have a 2006 let with a 2.9 TVS, 80# injectors, vibrant header, vibrant downpipe, 3 zzp cia. Going WOT About 4500 rpms I'm at 11.5 afr but just under 5000 rpms it goes super lean. Tried tuning it and it's not responding. Just replaced fuel pump and filter with acdelco parts I'd there anything else I can test that I may have overlooked. Rolling up the rpms is fine its just the sudden wot demand isn't there. Injector duty cycle at 42% when it goes lean.
Thanks in advance for any info

 

Fuel pump

 

Just swapped it and no change

 

you need to put more information out there are you on gas or e85

 

Idcs?

 

He said 42%

 

On 93 pump gas at the moment

 

I am having the same problem haven't changed fuel pump out yet but maybe it's com thing else??? I'm on e85 the but had 2.9 with tvs swapped back over to m62 with 2.7 and it's still happening

 

Anyone else ever have this issue??