This is a pretty common problem & I am sending info to repair your problem.
PIP3232B: Cold Engine Idle Misfire Or DTCs P0171 P0174 - keywords 4.8 5.3 6.0 air cold crack hesitate idle intermittent internal intake leak lean misfire miss P0171 P0174 P0300 power rough surge vacuum - (Feb 7, 2007)
This PI was superseded to update parts information. Please discard PIP3232A.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
99 through 05 GEN III truck engines may experience any of the following:
The intake gasket seals may be leaking around the intake ports, causing a lean condition. The intake gasket seals may leak around the bottom side of the port, making it a challenge to detect the vacuum leak. The technician may also notice lower than normal MAF readings if the intake seals are leaking.
Yes ,this should help.
Intake Manifold Replacement
Important: The intake manifold, throttle body, fuel rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.
This should help you.You will need a special tool that most parts suppliers keep in stock.
Metal Collar Quick Connect Fitting Service
Fuel Line Disconnect Tool
Caution: Wear safety glasses when using compressed air in order to prevent eye injury.
Notice: If necessary, remove rust or burrs from the fuel pipes with an emery cloth. Use a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface. Use a clean shop towel in order to wipe off the male tube ends. Inspect all the connections for dirt and burrs. Clean or replace the components and assemblies as required.
Caution: Always apply a few drops of clean engine oil to the male pipe ends before connecting the fuel pipe fittings in order to reduce the risk of fire and personal injury. This will ensure proper reconnection and prevent a possible fuel leak. During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.