Skip the auto shop - Our mechanics make house calls

Q: Bank 1 running to rich and injector 1 contribution fault Intermittent.

asked by on

've been getting misfires at idle when the car is hot, on cylinder 1 only (i'll see cylinder 3 sometimes but it's very minimum)

When first starting the car from cold in the morning, it will stumble a bit and then will run fine. I suspect that's because the car is already running rich so there is leftover gas.

I have a VCDS that I have been using a lot to troubleshoot this issue and this is my constant reading at idle.

Code: Address 01: Engine (8E1 910 559 F)

10:48:35 Group 032: Lambda Control (Mixture Adaptation) -16.5 % Adaptation (Idle) Bank 1 Sensor 1 -3.0 % Adaptation (Partial) Bank 1 Sensor 1 -10.0 % Adaptation (Idle) Bank 2 Sensor 1 -3.3 % Adaptation (Partial) Bank 2 Sensor 1

10:48:35 Group 033: Lambda Control -3.2 % Lambda Control Bank 1 Sensor 1 1.938 V Sensor Voltage Bank 1 Sensor 1 -3.7 % Lambda Control Bank 2 Sensor 1 1.938 V Sensor Voltage Bank 2 Sensor 1

10:48:35 Group 054: Idle Speed Stabilization 782 /min Engine Speed (G28) Idle Load

My car has 201000 miles.
My car has an automatic transmission.

A: Hi and thanks for contacting YourMechanic. ...

Hi and thanks for contacting YourMechanic. What you are experiencing is a misfire detected in cylinder 1 and a random misfire in cylinder 3. This could be caused by either the fuel injectors not firing, the spark plugs fouling out, or a possible blow by ring issue. What I recommend to do is check the injectors to see if they are working. With the engine running, you could remove the injector harness to the injector and see if the engine drops in RPM. If the engine drops in RPM, then the injector is working. If the engine stays the same, then the injector is not working.

With the engine off, you could remove the spark plugs from cylinder 1 and cylinder 3 and switch them with another cylinder. This will make the symptom change to other cylinders if the spark plugs are causing the problem.

If the injectors are working fine and the spark plugs are switched and your engine still is having trouble, then you would need to do a compression test. Check the compression on the first puff and then max out the puff. The pressure indicated on the first puff needs to be half or more of the final puff. If it is less than half, then the rings are probably worn. If all the problems are tested and checks out okay, then I would suggest having a professional, like one from YourMechanic, diagnose the misfiring issue properly so that this issue can be resolved.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Do i really need to replace the ignition coil?

There are ways to test the output of the coil before it reaches the distributor cap. Usually, if there is a problem with a spark plug wire, spark plug, or distributor cap, the problem is consistent. Those parts can...

Q: Refrigerant leaking from AC

It sounds like you have a leaking evaporator core. The replacement involves partial or full dash removal. Since you say it's coming from the vents, this may be dangerous. Long exposure to refrigerant can be harmful if inhaled for too...

Q: My buddies GM 4.3 liter just had the ignition modal replaced but now it runs and upon acceleration it sputters and backfires.

If the ignition module is new, it is more likely that the cause of the poor acceleration lies elsewhere. You can check to see if any diagnostic trouble codes have set using a code scanner. If there are no codes,...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.