Chevy Silverado 5.3L Fuel Injector Replacement — Everything You Need to Know

The Chevy Silverado 5.3L LS-based V8 is one of the most bulletproof truck engines ever built — but at high mileage, fuel injectors do wear out. The good news: the 5.3L's fuel system is straightforward, and replacing all 8 injectors is a job most mechanically experienced owners can complete in 3-4 hours.

This guide covers everything you need to know about Silverado 5.3L injector replacement — symptoms, diagnosis, step-by-step procedure, and costs.

Symptoms of Bad Injectors on the Silverado 5.3L

The 5.3L LS engine typically shows these symptoms when injectors are failing:

Rough idle or misfire — The most common symptom. You'll feel a stumble or shake at idle, and the check engine light will show misfire codes P0300-P0308. On the AFM (Active Fuel Management) 5.3, also check for lifter issues — AFM engines are prone to lifter failure that mimics injector symptoms.

Fuel smell from the engine — Old injector O-rings harden and crack, causing small fuel leaks. On a hot engine, this creates a fuel smell. Check the area around the fuel rail and injector bases for wet spots.

Poor fuel economy — A drop of 2-4 MPG combined with a rough idle points to injectors before other causes.

Hard starting after sitting — If the Silverado cranks 3-4 times before catching after sitting overnight, a leaking injector that's draining fuel pressure while the truck sits is the likely cause.

Step-by-Step: Silverado 5.3L Injector Replacement

Parts and Tools Needed

• 8x replacement injectors (Aurus part number A12668390 or 12634126 depending on year)
• New fuel rail O-rings (included with Aurus injectors)
• O-ring lubricant or clean engine oil
• 10mm socket
• Fuel line disconnect tools
• Shop rags

Step 1 — Relieve Fuel Pressure

Pull the fuel pump fuse (located in the underhood fuse box, labeled FUEL PUMP). Start the engine and let it stall. Crank it 2-3 more times to clear residual pressure. Replace the fuse when done.

Step 2 — Remove the Intake Manifold

On the LS 5.3L, the fuel injectors are under the intake manifold. You'll need to remove:

• Engine cover (if equipped)
• Air intake tube
• Throttle body linkage
• All vacuum lines and electrical connectors from the intake manifold
• 10 intake manifold bolts (10mm)

Lift the manifold straight up. Cover the intake ports immediately with shop rags.

Step 3 — Remove the Fuel Rail

You'll see both fuel rails (one per bank) with 4 injectors each. Disconnect the fuel feed line from the driver's side rail. Unplug all 8 injector electrical connectors.

Remove the 4 fuel rail bolts per side (8 total, 10mm). Rock each rail side to side while pulling up to release the injectors from the intake ports.

Each injector is held to the rail by a small retaining clip. Pop the clip with a flathead screwdriver and pull the injector straight out.

Step 4 — Install New Injectors

Lightly oil the new O-rings. Press each new injector into the fuel rail until the retaining clip snaps. Lower both rails onto the intake manifold, align all 8 injectors with their ports, and push down firmly until all injectors seat. Reinstall all 8 rail bolts.

Step 5 — Reinstall Intake Manifold

Clean the intake manifold gasket surface. Install new gaskets. Lower the manifold straight down and torque the 10 bolts to 89 inch-pounds in sequence (start from the center and work outward).

Reconnect all vacuum lines, electrical connectors, and the fuel line.

Step 6 — Prime and Start

Cycle the ignition 3 times (key to ON, wait 5 seconds, key to OFF) to build fuel pressure. Check for leaks. Start the engine — it may take a few extra cranks on the first start.

Part Numbers for Silverado 5.3L Injectors

• 1999-2006 5.3L: ACDelco 25317628 / Bosch 0280155715
• 2007-2013 5.3L: ACDelco 12634126 / Bosch 0280158189
• 2014+ 5.3L: ACDelco 12609749 / Bosch 0280158413

Cost Comparison

Option	8 Injectors Total
Aurus remanufactured (DIY)	$280-360
OEM ACDelco (DIY)	$600-800
Independent shop (parts + labor)	$900-1,400
Dealership	$1,400-2,000

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