I have a 2001 Dodge Ram 2500 Cummins Turbo Diesel and lately it's been sluggish when I switch gears. It is a manual. Anyway, when i went to Autozone for them to check what was wrong it said that the Turbo Boost Sensor "A" pressure was too low for the engine. So that's why it is pulling it down.

Ok my questions are... :confused:

Where is the Turbo Boost Sensor "A" at?

How do i go about fixing it?

check for leaks first. a bad boot or somthing.

it says your underboosting.
your sensor is probably fine.

you have an intake leak, fuel delivery issue, or restricted air inlet are the most common.
but also can be mechanical problems like a stuck wastegate or other issues.

AKA map sensor. Check to see if the wires are still attached, otherwise it's about a $100 part and as far as I know, autozone doesn't sell it. NAPA does though as a "turbo boost sensor". On the rear drivers side of the block at the bottom of the head right behind the fuel filter.
If it's faulty or disconnected it will cause the engine to go into a limp mode of sorts and run at half power.

Otherwise, you need a boost gauge and an FSM to test the MAP sensor.

Not sure if you're still having the problem or not, but it sounds like the same problem I had on my 2001 Dodge. You can replace the map sensor at the back of the block if you want or you can remove the old one and instert a small screw driver into the port and GENTLY push the plunger back several times. I got this tip from another Cummins guy and it worked great for me. Beats paying 100 plus dollars for a new sensor!!!!