Quick answer: Injector & Intake Manifold Service on a 2014–2024 Infiniti Q50 is rated Advanced and takes about 2-3 hours. You'll need 9 tools for this job, and parts cost about $65. This guide walks you through the full job step by step, including the mistakes to avoid.
| Part Name |
Part Number |
Price |
Buy |
| Intake Manifold Gasket |
14035-6N21A |
$30.00 |
|
| Fuel Injector O-Rings |
16678-6N21A |
$15.00 |
|
| Throttle Body Gasket |
16176-6N21A |
$20.00 |
|
About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.
💡 Pro tip: Order all parts at once to save on shipping
Step-by-Step Instructions
Follow these steps carefully
1
Scan codes and cool the engine
Note misfire, fuel-trim, or intake-related codes. Work only on a cold engine. Disconnect the negative battery cable. Relieve fuel pressure per the service manual before opening any fuel lines.
🔧 Mechanic's note — Tom Becker
I scan the Q50 codes and disconnect the negative first — on last after the injector service. Fuel system open plus electrical live is a combination I refuse, so the cable order is non-negotiable for me.
2
Remove intake plumbing and electrical connectors
Remove the engine cover, air intake tube, and any brackets blocking the manifold. Label and unplug injector connectors, MAP/MAF sensors, and vacuum/EVAP hoses. Photograph routing before disconnecting.
🔧 Mechanic's note — Tom Becker
I remove the Q50 intake plumbing and unplug the connectors, noting each lock type — they go back with a click each. I have seen a dozen connectors on jobs like this, and the one I do not seat throws the code.
3
Remove the fuel rail and injectors
Disconnect the fuel supply line with the correct quick-connect tool and catch residual fuel. Replace all injector O-rings and rail seals — do not reuse swollen O-rings.
4
Remove and clean the intake manifold
Unbolt the intake manifold in the specified sequence. Lift it straight off; plug open ports immediately. Clean carbon from the ports, throttle body flange, and injector seats with intake-safe cleaner. Do not let debris fall into the cylinder head ports.
5
Reinstall manifold, injectors, and rail
Install a new intake gasket set. Torque manifold bolts in sequence to spec. Lubricate new injector O-rings lightly with clean engine oil, seat injectors, and torque the rail. Reconnect fuel and electrical connections until they click.
6
Pressurize, leak-check, and verify idle
Reconnect the battery, cycle the key to pressurize the fuel system, and inspect for leaks before starting. Start the engine, confirm smooth idle, clear codes, and road-test while watching fuel trims if a scan tool is available.
🔧 Mechanic's note — Ray Delgado
I pressurize the Q50 fuel system and leak-check it, then I start it and watch the idle — a leaking injector or loose manifold seal shows as a rough idle or fuel smell that never appears with the engine off.
All Done!
Test your repair before closing everything up. If something doesn't work right, double-check your steps.
⚠️ Common Mistakes to Avoid
- • Forgetting to disconnect the battery before starting work
- • Not properly labeling vacuum hoses and electrical connectors, leading to reassembly issues
- • Failing to replace gaskets and O-rings, causing potential leaks
