Faulty ignition coil on cylinder 3; Worn or fouled spark plug on cylinder 3; Failed fuel injector for cylinder 3 (clogged, leaking, or electrically open); Vacuum leak at the intake manifold near cylinder 3; Mechanical issue such as low compression, worn camshaft lobe, or faulty lifter on cylinder 3; Damaged wiring or connector to the cylinder 3 ignition coil or injector; Contaminated fuel or fuel pressure problem affecting cylinder 3

DTC codes / BMW codes / P1347

P1347 · BMWMisfire Cylinder 3 With Fuel Cut-off

Q: What does code P1347 mean?

Misfire Cylinder 3 With Fuel Cut-off. P1347 on a BMW indicates that the engine control module (ECM) has detected a misfire on cylinder 3 and has responded by cutting off fuel delivery to that cylinder to protect the catalytic converter from unburned fuel. The ECM monitors crankshaft speed fluctuations to identify the misfire and then disables the fuel injector for that specific cylinder.

P1347 on a BMW indicates that the engine control module (ECM) has detected a misfire on cylinder 3 and has responded by cutting off fuel delivery to that cylinder to protect the catalytic converter from unburned fuel. The ECM monitors crankshaft speed fluctuations to identify the misfire and then disables the fuel injector for that specific cylinder.

SystemPowertrain

Code typeBMW specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illuminated check engine light, often flashing if the misfire is severe
Noticeable engine shaking or rough idle, especially when cold
Reduced engine power and poor acceleration
Increased fuel consumption due to the cylinder being shut down
Possible rotten egg smell from the exhaust if unburned fuel reaches the catalytic converter
Often no symptoms besides the warning light if the misfire is intermittent or minor

Common causes, most likely first

Faulty ignition coil on cylinder 3
Worn or fouled spark plug on cylinder 3
Failed fuel injector for cylinder 3 (clogged, leaking, or electrically open)
Vacuum leak at the intake manifold near cylinder 3
Mechanical issue such as low compression, worn camshaft lobe, or faulty lifter on cylinder 3
Damaged wiring or connector to the cylinder 3 ignition coil or injector
Contaminated fuel or fuel pressure problem affecting cylinder 3

How to diagnose and fix it

Perform a visual inspection of the cylinder 3 ignition coil, spark plug, and injector connectors for damage or corrosion
Swap the ignition coil from cylinder 3 with another cylinder and see if the misfire moves, confirming coil failure
Remove and inspect the spark plug from cylinder 3 for wear, fouling, or incorrect gap; replace if necessary
Test the fuel injector for cylinder 3 with a noid light or multimeter to check for electrical signal and resistance
Run a compression test on cylinder 3 and compare with other cylinders to rule out mechanical problems
Check for vacuum leaks using a smoke machine or carburetor cleaner around the intake manifold
If all components test good, perform a fuel pressure and injector balance test to identify fuel delivery issues

Before replacing the fuel injector

A misfire code P1347 can be set by a simple vacuum leak at the intake manifold gasket, which is often overlooked because the leak affects multiple cylinders but may trigger the code on the weakest one first.
BMW engines are known for ignition coil failures that can cause a misfire without setting a coil-specific code; swapping coils is a quick and free diagnostic step.
The fuel cut-off is a protective strategy, so the injector itself may be functioning perfectly; the ECM has disabled it due to the misfire, not necessarily because the injector failed.
A worn spark plug or incorrect gap can cause misfire under load only, so the code may not appear during idle; always test under load conditions.
Low compression on cylinder 3 due to a faulty valve or piston ring can mimic an ignition or fuel issue, so a compression test is essential before replacing parts.

Can I keep driving with P1347?

It is not advisable to drive with a flashing check engine light or severe misfire, as unburned fuel can overheat and damage the catalytic converter. If the light is steady and the misfire is mild, you may drive cautiously to a repair shop, but avoid hard acceleration and prolonged driving.

Tools that help

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Guidance is general and written for BMW vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.