Follow up.
It was my fuel filter causing the drop in rail pressure. Had it replaced and all is good there.
Still have code P0102 though

Does the puck "fool" the rail pressure in the same sense as it fools the boost? Meaning does it show lower rail pressure on an electronic guage when the knob is cranked?

Thanks for the reply Mike.
I put three shims in so I don't think it's that. I think it may be dropping the rail pressure after the MAF code/error maybe?

2008 lmm duramax
Fully installed and shimmed also.
Throws P0102 code when I get on it hard and have the knob turned up more than ~30%.
Fuel pressure drops to 10000k.
Also boost on my electronic boost guage goes down to 20psi from 25psi on max effort when I hve the knob turned all the way up..
Is ...

how many miles do you have on that 07?

waiting patiently

I guess I should have been more specific.. I am a Dodge Ram owner..
Mainly wondering about difference for transmission and the LX forum cannot help there..
But thanks for the reply anyhow..

I have a superchips tuner... Is there someone around that has tried both?
I am just wondering how the tunes compare.. Do they feel different? What about shifting? etc..