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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Pinging sound a

Hey there, thanks for writing in about your 2012 Cadillac Escalade. A pinging noise is typically used to refer to spark knock or a damaged engine running condition. Did the Check Engine Light return with the same codes after doing...

Q: Key turns in the ignition but car won't start

The remote may need the battery replaced. Try another good remote, or change the batteries in the remote. If this does not work, then you may have to get the antitheft system tested using the dealer's scanner. This will test,...

Q: Car won't pass smog.

Hello! I will be happy to assist you. On your particular vehicle, random misfires are commonly caused by things such as low fuel pressure, a faulty oxygen sensor, bad vacuum lines, or faulty air flow sensors; a broken or loose...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.