You are flooding the motor at an AFR of 7.3 to 1. More than likely the stuttering you are talking about is so much fuel being added between the gas and alky that you are blowing out the spark. You should be shooting for an AFR of 10.5 to 1., 11 to 1 is ok with less timing. And back the timing down to 21 degrees, 24 is great for a dead on tune but if its not then you can pop a head gasket easily.
You have good voltage to everything, that is a plus. You dont list whether you have a single or double pump set up. If its a single you are fine, if its a double that would explain a couple of things. If you do have a double pumper, turn it off. You only need one good in tank pump, the alky takes care of the rest.
Back the boost off to 10 psi, i know it will feel slow right?, run at 10 psi and see what it does. If it is running well at that level then turn it up to 15, then 20 and so on. 26 psi with 25 degrees of timing is a bunch of power but you have to make sure it is tuned correctly.
Rules of thumb. Set the alky turn on point at 8 psi and leave it alone. Turn the gain knob to 6. Turn the timing down to 20 degrees so you dont blow it up. Ask me how I know.
If you have a double pumper, turn off the second pump it is now overkill. What happens is the second pump kicks on at a set boost level and you double the volume of fuel going to the injectors. The ECM can only take out so much to try and compensate. It wont be enough. Add twice the amount of fuel and the alky on top and you get a pig rich motor that runs like crap and you cant figure out why.
Your TT chip can be changed up easily, grab the instruction sheet that came with it. If you dont have that go to Eric's website. Instructions are listed there. I am assuming you gave him all the info he needed to burn the chip correctly for your combo.
Hell I run mine at 21 psi and 20 degrees timing and there is not much that keeps up with me. Yours should be faster.
Good luck.
