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I have a 2012 BMW 740li. The Drivetrain Malfunction light…

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I have a 2012 BMW...
I have a 2012 BMW 740li. The Drivetrain Malfunction light has been coming on, the car hesitates now when I press mroe than 25% OF THE GAS PEDAL, and shakes when I come to a stop. I also smell gas sometimes and sometimes it doesn't start right away. I added fuel injector cleaner to the gas, but nothing has changed. What kind of problem am I looking at?
Submitted: 1 month ago.Category: BMW
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1/7/2018
BMW Mechanic: Steve, BMW Expert replied 1 month ago
Steve
Steve, BMW Expert
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Have the faults been read ?
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Customer reply replied 1 month ago
No, will the local auto store do that?
BMW Mechanic: Steve, BMW Expert replied 1 month ago

is the check engine light or service engine soon light also on?

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Customer reply replied 1 month ago
Check engine light is on.
BMW Mechanic: Steve, BMW Expert replied 1 month ago

Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you

a parts store can read out generic codes if the check engine light is on, although these are not the best codes to use on this vehicle for an accurate diagnosis

your symptoms suggest an air leak, failed crankcase ventilation system or turbo issue, but the faults will need to be scanned as a first step in narrowing down possible causes.

if you need a good non dealer option to cut down on costs, check out www.bimmershops.com or www.bimrs.org for options.

Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle.

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Customer reply replied 1 month ago
OK I have my codes and would like if you can give me an idea of what is likely the problem:
P0300
P0302 Cylinder 2 Misfire
P0303 Cylinder 3 Misfire
P013E Sensor Delayed Response (Rich to Lean Bank 1 sensor 2)Since this is the first time that this drivetrain malfunction light came on, so whatever happened...happened at once. If it helps, shortly before it happened I was driving faster than I normally do.
BMW Mechanic: Steve, BMW Expert replied 1 month ago

Please do not forget to click a positive rating

most likely bad plugs or coils on cylinders 2 and 3, as well as a potential intake air leak, failed crankcase ventilation system or airflow sensor causing a mixture issue. Please do not forget to click a positive rating

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Customer reply replied 1 month ago
You wrote: "most likely bad plugs or coils on cylinders 2 and 3."Is it likely that the plugs or coils would fail at the same time?
BMW Mechanic: Steve, BMW Expert replied 1 month ago

Please do not forget to click a positive rating

both plug and coil on the same cylinder - no.
two plugs or two coils on different cylinders at the same time - yes possible.
you can just swap them around to different cylinder to verify. Please do not forget to click a positive rating

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Customer reply replied 1 month ago
On my vehicle 2012 740il, which would be Cylinder 2 and 3?
BMW Mechanic: Steve, BMW Expert replied 1 month ago

one is the front most, 2 in the next towards the back. As the question has been answered please kindly select a positive rating

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Customer reply replied 1 month ago
I'm sorry but I'm trying to make sense of this. Wouldn't it be rare for 2 separate cylinders to get either bad coils or plugs at the same time? In other words, just having one of these go out would have probably tripped the computer check engine light, which makes both going out at the same time very rare. Would you agree?
BMW Mechanic: Steve, BMW Expert replied 1 month ago
no I wouldn't agree.
the plugs and the coils have the same wear and mileage on them with the same anticipated service lives. So, they can and do go out at the same time.
Regardless - you can just swap them around and know for sure without incurring any costs so there is really no risk... if the misfires stay in those cylinders or become totally random then you know it isn't the plugs or coil and can look for a cause of lean running, per the rest of my answer. Please do not forget to click a positive rating
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Customer reply replied 1 month ago
OK, I went ahead and replaced both the spark plugs and the coils. Unfortunately no change, drivetrain malfunction light appears and the codes still exist:P0300
P0302 Cylinder 2 Misfire
P0303 Cylinder 3 Misfire
P013E Sensor Delayed Response (Rich to Lean Bank 1 sensor 2)When I changed the plugs I noticed that plug on cylinder number three appeared to have a significant carbon buildup. After changing all of the plugs, driving the car for only 5 miles, I wanted to see what plug #3 looked like. Attached is the new plug after only 5 miles! Obviously there is a problem as the plug is black and smells like gasoline.
BMW Mechanic: Steve, BMW Expert replied 1 month ago

Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you

you have a bad injector or compression issue on that cylinder.

regarding the other codes it still suggests a lean running issue as I previously outlined. Please do not forget to click a positive rating

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Customer reply replied 1 month ago
What could be causing the compression issue based on the blackening of the spark plug after only 5 miles?As for the other lean running issue, it sounds like that is a result of the unburnt fuel coming from the misfiring cylinder/s?
BMW Mechanic: Steve, BMW Expert replied 1 month ago

Please do not forget to click a positive rating

lean running is not enough fuel, not too much fuel.

the compression issue would be a bad ring, cylinder or piston wear, or a valve issue. Please do not forget to click a positive rating

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Customer reply replied 1 month ago
OK so to clarify: P013E Sensor Delayed Response (Rich to Lean Bank 1 sensor 2) - is probably a situation that is caused by the cylinder, and NOT what is causing the cylinder to miss?
BMW Mechanic: Steve, BMW Expert replied 1 month ago

that one cylinder clearly has a problem. the others and the random miss is probably caused by the lean condition. Please do not forget to click a positive rating

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Customer reply replied 1 month ago
Using the many clues I've given you, with your experience, can you tell if it's a blown head gasket, Piston rings, or bad injector? Is there anything else I can try?
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