I would look more in to this (bold in quote). If map is steady and the calculated airflow drops, I suspect there is hole in a MAF table or the MAF itself is bad. You could also check all the plumbing behind the MAF to make sure there are no leaks. Are you injecting anything pre-maf such as meth or nitrous?

 

Not running meth or nitrous. I have another maf that I am going to put on to see if it will fix it but it has been work fine up till now so I bet there is a issue in the maf tune.

 

well took the tune from the 2005 and copy and pasted it to my tune and did a write intire instead of a calibration only. It fixed the problem for the most part. I still had to put a maf tune from my buddys 03 ss silverado with a mp112. It was still a little lean but was not just suddenly droping like before. After i did the maf tune it is almost perfect just needs a little fine tuning. Thanks for all the responses and help.

 

Did you have to scale the injectors for the Return style fuel system?

I believe that's one of the small differences.

 

My friend wrote the tune for me and he said he didn't have to touch it for some reason it wasn't set for return less but it did have 37# injectors. He just left those values in there for now and overall it was looking pretty good. Around 11.5 on the wide band with zero knock. So with a little bit more fine tuning it should be good to go.

 

I was wrong it was 39# injector values

 

I think... If I remember correctly...

On the 99-03 Return style, the value is constant as the vacuum regulates the pressure.

On The 04-up return Less style the value increase as the MAP value increases or something like that since the fuel pressure remains the same.

 

ya your right i meant to say it was set for return style. It was set to 39# across the whole table instead of increasing.