How to replace fuel injectors in 2005 trailblazer 4.2

OH there are bolts on each side and pull up. If I remember correctly there not enough play to pull one side up without removing the bolts from the other side. Just remove all the hold-down bolts and pull up. You might need a helper to line up the injectors on the other side during installation.

if you need detailed step by step process, please click the link below and follow the instructions with diagrams.

How to remove fuel rails on 1999 v10 6.8

this will help.

Silverado 1500 or 2500 or 3500 or HD? no pickup told
not told the job you are doing>??
remove them all ,or scope them or just what, no job told
no end goal or task told. sorry can guess it.

like most V6/8 now , it is a sandwich.
the service manual covers all,l buy it rent it.?
toss dice and land on 1500
the rail on this engine, fuel rail like all , intake manifold injectors used;. all injector held down by both rails. left and right
now the steps to off them if is the job,
pull the isolator seen photo 1, far below.
1: pull left rail and right rail
Remove and discard the fuel injector retainer clips by installing EN-51097 injector retaining clip installer and spreading both sides of the clip evenly.
Always use NEW fuel injector collars supplied with injector when installing the new injector. If reinstalling the injector, it is not necessary to remove the collars unless the collars are being replaced.
Replace the injector seals as needed. Refer to Fuel Rail and Injectors Cleaning and Inspection.
Note
Inspect the injectors to be sure that they are clean and free of debris prior to installation. Do NOT lubricate the injector seals. Rebuild the fuel injectors whenever the injector has been removed from the fuel injector rail.


now I will past the other page rails off per the manual read to you.
just bank 1, i am to lazy to post both
step 1 rail off bank1.
Note
Inspect the injectors to be sure that they are clean and free of debris prior to installation. Do NOT lubricate the injector seals. Rebuild the fuel injectors whenever the injector has been removed from the fuel injector rail.

1. Remove the fuel pump insulator. Fuel Pump Insulator Replacement
2. Remove the fuel injector intermediate pipe position?1. Fuel Feed Intermediate Pipe Replacement - Position 1
3. Clean the cylinder head pocket around the injectors of any dirt or buildup.
4. Disconnect the electrical wiring harness connectors from the fuel rail.
5. the fuel rail fasteners are retained in the fuel rail by keepers and may be difficult to remove.Remove the fuel rail fasteners?(1) securing the injector rail?(2).
   Install two sets of EN-49248 remover?(3).
6. Install one remover in each of the fuel rail fastener bores.
7. Remove by turning each section of the EN-49248 remover an even amount to pull the fuel rail and injectors out evenly.
8. CAUTION
9. Remove the fuel rail assembly carefully in order to prevent damage to the injector electrical connector terminals and the injector spray tips. Support the fuel rail after the fuel rail is removed in order to avoid damaging the fuel rail components.
10. Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages.
11. 1. Simultaneously lift both ends of the fuel rail?(2) and remove the fuel rail assembly from the cylinder head.
12. Remove and DISCARD the fuel injector seals.
13. Some vehicles were not originally equipped with fuel injector dust seals. A NEW seal must be installed when the injectors are removed.
    Remove and DISCARD the fuel injector dust seal (1).
14. NOTE
    Note
    Whenever the fuel injectors are removed from the cylinder head or fuel rail, they will need to be rebuilt. Fuel Rail and Injectors Cleaning and Inspection
    If replacing the fuel injection fuel rail, remove the fuel injectors. Fuel Injector Replacement

Installation Procedure, skipped me. the service manual lists 4 tools
per

Special Tools

1. EN-49248 Injector Rail Assembly Remover
2. EN-51105-1 Injector Seal Installer and Sizer
3. EN-49245-3 Fuel Injection Seal Installer Sizer
4. EN-49245-4 Fuel Injection Seal Installer Sizer

this is first. pull the isolator.

this one step is the GET TO ANSWEREd
Injector work 10x more complex and special tools needed x4

Very carefully, there should be locks on top of injectors or you can pull injectors and rail all together

remove the bolts that hold the fuel rail. Lift the fuel rail, pulling the injectors out carefully. Make sure the rubber seal comes out with the injector. Remove the electrical clip for the injectors you want to change. Clip in the new injector, and replace the fuel rail and the injectors.

Take the engine cover off

Find the fuel leaks & resolve them

To replace the fuel injectors,first the fuel pressure needs to be relieved, then remove engine appearance cover.Then remove air cleaner and air cleaner ducting.Then comes vacuum hoses,remove the hoses and electrical connectors that prevent you from accessing the fuel rail. Disconnect the fuel send and return lines and unplug the electrical connectors for the fuel injectors. -------- You will need socket wrench to relieve fuel pressure and to remove bolts on fuel rail. Complete fuel rail assembly will come out with injectors,then you will have to remove injectors from fuel rail. -------- With new fuel injectors use new O-ring.Don't use old O-ring,use new O-ring. ---------- This will help.Thanks.Helpmech.

You didn't post the size of your engine so please pick the appropriate one:

3.8L

1. Relieve the fuel system pressure.
   
2. Drain the cooling system.
   

1. Remove or disconnect the following:
2. Negative battery cable
   

• Supercharger
  
• Thermostat housing
  
• Exhaust Gas Recirculation (EGR) tube at the intake manifold
  
• Engine Control Temperature (ECT) sensor
  
• Intake manifold
  

To install:

1. Install or connect the following:
   
   • Intake manifold with new gaskets. Torque the bolts, working from the center out, to 11 ft. lbs. (15 Nm).
     
   • ECT sensor connector
     
   • EGR tube to the intake manifold
     
   • Thermostat housing
     
   • Supercharger
     
   • Negative battery cable
     
2. Refill and bleed the cooling system.
   
3. Run the engine and check for leaks and proper engine operation.
   

4.6L
4.6L Engine

1. Remove the brake booster hose from the throttle body.
   
2. Remove the fuel pressure regulator vacuum tube from the fuel pressure regulator and the water crossover.
   
3. Remove the PCV fresh air feed tube from the camshaft cover and the throttle body.
   
4. Remove the PCV dirty air tube from the PCV orifice in the right camshaft cover and from the intake manifold.
   
5. Disconnect the fuel injector electrical connectors from the fuel injectors.
   
6. Remove the fuel injector wiring harness.
   
7. Remove the fuel rail bracket nut from the engine lift bracket.
   
8. Remove the fuel rail studs.
   
9. Lift and remove the fuel rail with injectors.
   
10. Loosen the plenum duct clamp in order to remove the intake manifold.
    
11. Remove the intake manifold bolts.
    
12. Remove the intake manifold.
    

To install:

1. Install the intake manifold, fitting the plenum duct over the intake manifold duct.
   
2. Loosely install the intake manifold bolts.
   

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Intake manifold torque sequence-4.6L engine

2. Tighten the intake manifold bolts in sequence. Tighten the intake manifold bolts to 89 inch lbs. (10 Nm).
   
4. Tighten the plenum duct clamp to the intake manifold. Tighten the plenum duct clamp to 24 inch lbs. (2.75 Nm).
   
5. Inspect the fuel injector O-rings. Ensure the fuel injector O-rings are not missing, misaligned or damaged. Replace the O-rings if necessary.
   
6. Lubricate the intake manifold fuel injector bores with light mineral oil (GM P/N 9981704), clean engine oil, or equivalent.
   
7. Install the fuel rail with fuel injectors as an assembly.
   
8. Install the fuel rail studs. Tighten the fuel rail studs to 80 inch lbs. (9 Nm).
   
9. Install the fuel rail bracket nut to the engine lift bracket. Tighten the fuel rail bracket nut to 89 inch lbs. (10 Nm).
   
10. Install the fuel injector wiring harness.
    
11. Connect the fuel injector electrical connectors to the fuel injectors.
    
12. Install the PCV dirty air tube to the PCV orifice in the right camshaft cover and to the intake manifold.
    
13. Install the PCV fresh air feed tube to the camshaft cover and the water crossover.
    
14. Install the fuel pressure regulator vacuum tube to the fuel pressure regulator and the throttle body.
    
15. Install the brake booster hose to the throttle body.
    

Maybe an O-ring is leaking. Try a new injector that comes with an o-ring to be sure it's not the injector itself.
Fuel Injector - for V8

REMOVAL & INSTALLATION

1. Before servicing the vehicle, refer to the precautions in the beginning of
   this section.
   
2. Relieve fuel system pressure.
   
3. Remove or disconnect the following:
   
   
   
   • Negative battery cable
     
   • Fuel rail
     
   • Fuel injector retaining clips
     
   • Fuel injectors
   
   To install:
   
   
4. Install or connect the following:
   
   
   
   • Fuel injectors, using new O-rings
     
   • Fuel injector clips to the fuel rail
     
   • Fuel rail
     
   • Negative battery cable
   
   
5. Start the vehicle and check for leaks, repair if necessary.

The procedure to replace the fuel injector in Buick Lesabre Is as follows:-- 1) you will require a ordinary flat screwdriver, a needle nose pliers, a 10 mm socket, 6" extension and 1/4" ratchet. 2) First of all take the engine cover out then pinch the fuel rail connecting fittings at the base and lift off the two hoses. Note:-- Do this when your engine is cold. 3) Then bleed off the pressure in the fuel rail first. Take care you don't damage the fuel rail while bleeding the fuel pressure because a new one will cost over $ 200. 4) Loosen and remove the four nuts holding down the fuel rail. Disconnect all six electrical connectors to each injector. 5) Carefully lift up the fuel rail. Pry off the clip holding the top of the injector to the fuel rail. Pull the injector out of the fuel rail and then out of the intake manifold. 6) Install the new injectors and replace top and bottom o-rings. Reassemble and check for any fuel leaks. Thanks.

Easiest way is just wrap a rag around or sometimes there is a bleeder like a tire has on the fuel rail. Now the only things that can be leaking is the Fuel Rail or The Injectors Orings or the Fuel Supply Line.
Hope this helps