Huge hesitation, mechanically inclined. Please help

You said you finally got a CEL- what was the code(s)? When a code is set, you can get a freeze frame for it with better scan tools, especially a Modulus and TechII. A freeze frame is highly valuable to diagnosing issues such as this.

Unfortunately the CEL was just a p442 evaporated code

I believe we tested the crank sensor as well

OK all those sensors "should" be good then?? Still it would not hurt to check then with a DVOM meter. On my 951 (Porsche 944 turbo S) I refused to belive my newly installed Fuel Pressure gauge that kept reading 0??? Despite the fact that I had installed not one but two new fuel pumps???

Finally I stuck the new fuel pump in a freakin gas can with hoses on the end in and out applied 12 volts ... despite the fact that I could heard the pmp running ... it did nothing???

Just cause the part is "new" does not necessarily mean it works ... apparently???

FIGURED OUT THE PROBLEM!!!
kinda...
Alittle history I assumed was unrelated. I had a brake caliper dragging awhile back on passenger side front. So I replaced it, replaced pads and rotor on both sides and vacume bleed them. The next day it locked up again. So I replaced the flex hose going to the caliper and vacume bleed it. I thought the problem was fixed. This was months ago. Today I jacked the front end up to pull the front differential out to check it out inside. I noticed the passenger side wheel had alot of drag on it when I leaned on it. So I open the bleeder valve and it had pressure. Fed up with it, I replaced both front calipers, pads, rotors again. This time I used a snap on modis 2 auto bleed program to bleed each wheel. Well, my master cylinder decided to go out during the process so I bought a new one. All components used this time were brand new, not remanufactured. Installed and auto bleed again. Thought everything was great. Drove about 2 miles. And noticed the brakes were dragging ALOT. Cracked the bleeder on both front brakes and had pressure. Then drove the truck 21 miles home with no issues and absolutely no hesitation for the majority of the trip. And when I got home just for shit and giggles, I feel the wheels and they are hotter than they should be. Cracked bleeders, pressure but not near as much. Also noticed my pedal feels soft when I first let pressure out but as I use brakes driving, the pedal gets more firm.

So, long story short, brakes dragging was my entire problem that I have been having. Now the problem is why do they keep holding pressure? Brand new master cylinder and calipers and rubber hoses. So it must be in the brake booster or abs pump assembly?

Nice to know the cause of the problem, now on to the solution. And I have no ideas as of yet to why that would be happening. Do you have Hydroboost?

I don't know. It's all stock

Ok ... that sounds "Seriously Messed Up" so to be clear ... not an "Engine Issue" then???

It was not an engine problem. I don't have hydroboost. Also, this looks like a very common problem on newer gmc trucks. Most people say pulling the abs fuse fixes the problem. A few say bad brake booster will cause it. I also noticed the rod going thru the firewall to push the master cylinder piston is adjustable. I might need to adjust it in a bit if it is holding pressure on the piston.

Ugh ... "speculating here" and considering the timing being pulled thing??? PCM would be cutting power "Traction Control" so the "PCM" thinks the vehicle is outa control. So that kinda makes sense, disabling ABS is a work around but obviously ... not ideal.

Maybe you have a bad brake line???