Detroit 12.7 Hard Start and No Power

at that point look to the charge air cooler and valve adjustment, also the injector impulse rate. these are just ideas, not gospel.

 

Is this really getting into it? Trying to race to the top of the hill? If so, assuming that gauge isn't bad, that's a definate problem.
If it was my truck, I would first pressure check the air to air by plugging the inlet and outlet and supplying 40 pounds of pressure. See how much it loses after 2 minutes. If more than 2 pounds or so, I'd replace that with a good quality after market one. But before this, using soapy water in a spray bottle, soak everything down from the turbo to the intake. Start the truck and look for bubbles. It could be as simple as a broken turbo clamp on the rubber boot.

also pull the exhaust pipe from the back ofthe turbo and run your hand asking the turbine shaft and fins. Do the same on the cold side. You are looking for oil.

This is all stuff you can do on your own. No need to pay a shop for this.

 

Then time to look for the air leak. If there is no major leak, then I would question those injectors you just put in. How did you aquire them? Was it from Detroit or wee they after market? If after market there is about a 99 percent chance they are calibrated wrong.