[2k11PDXE90]

2011 328i M-Sport Auto Trans with paddles.
The only modification to the car I have it an Injen intake.
I bought this car from a local BMW Dealer about 2 months ago. After driving it the initial few weeks I noticed an issue where the car fails to accelerate, or stumbles when I hit the accelerator. This is very intermittent and it usually happens in the morning. For example when I was pulling out of my neighborhood I start out slowly and then press the accelerator down more aggressively, the car will fail to accelerate, jerk back and fort a little, like it's trying to switch up and down gears, the RPM goes up and then it finally accelerates. I notice this more when I'm turning and hit the gas accelerating into the turn. I went to the BMW Dealer, told them the issue, the had the car for a week, and finally told me it was the vanos and there was a bolt that backed out and others were loose. They fixed the vanos and I was on my way. Well, the issue above is still happening. It's intermittent, an no lights are thrown. I would like to get this resolved before my dealer warranty expires. Thanks to all in advance.

[rjahl]

Originally Posted by 2k11PDXE90

2011 328i M-Sport Auto Trans with paddles.
The only modification to the car I have it an Injen intake.
I bought this car from a local BMW Dealer about 2 months ago. After driving it the initial few weeks I noticed an issue where the car fails to accelerate, or stumbles when I hit the accelerator. This is very intermittent and it usually happens in the morning. For example when I was pulling out of my neighborhood I start out slowly and then press the accelerator down more aggressively, the car will fail to accelerate, jerk back and fort a little, like it's trying to switch up and down gears, the RPM goes up and then it finally accelerates. I notice this more when I'm turning and hit the gas accelerating into the turn. I went to the BMW Dealer, told them the issue, the had the car for a week, and finally told me it was the vanos and there was a bolt that backed out and others were loose. They fixed the vanos and I was on my way. Well, the issue above is still happening. It's intermittent, an no lights are thrown. I would like to get this resolved before my dealer warranty expires. Thanks to all in advance.

Sounds like the DSC system or traction control. Do you have good sticky tires or hard slippery and cold tires?

Try the same test but place the transmission in second gear.

[AWSB328iM]

Whats your mileage? Anything above 60K miles you need to change the spark plugs. I had these exact symptoms at 60K which is the BMW recommended maintenance interval for plugs on a LCI 328I.

[2k11PDXE90]

rjahl BMW put on new factory spec runflats at the time of my purchase.

AWSB328iM I'm at 56k miles. I was thinking the plugs or coils may cause this issue, though I would have expected a CEL if it was either of those? Though if you had the exact same symptoms, I'll go get some plugs. Did you use factory plugs or other? If other, which ones and what's your experience with them?

Thanks Much!

[AWSB328iM]

Originally Posted by 2k11PDXE90

rjahl BMW put on new factory spec runflats at the time of my purchase.

AWSB328iM I'm at 56k miles. I was thinking the plugs or coils may cause this issue, though I would have expected a CEL if it was either of those? Though if you had the exact same symptoms, I'll go get some plugs. Did you use factory plugs or other? If other, which ones and what's your experience with them?

Thanks Much!

Plugs won't cause a CEL. I used the factory recommended NGK plugs. BMW Part Number is 12120037663 or NGK # LZFR6AP11GS. They are on eBay for $57 for a set of 6 with free shipping. Make sure you gap them to .44 as they came out of the box gapped around .30

It took me around 1 hr to swap the plugs start to finish.

[rjahl]

Originally Posted by AWSB328iM

Plugs won't cause a CEL. I used the factory recommended NGK plugs. BMW Part Number is 12120037663 or NGK # LZFR6AP11GS. They are on eBay for $57 for a set of 6 with free shipping. Make sure you gap them to .44 as they came out of the box gapped around .30

It took me around 1 hr to swap the plugs start to finish.

I'm not going to say that your plugs are fine but I would suggest just checking a second gear pull from a near stop. At one time, my car did the same thing at it was just slippery tires. The DSC would kick in and cut the engine power. It would then slowly bring the power back on. Doing a second gear take off from start will tell you if the engine is truly faulty or if the DSC trying to save you from yourself.

Why not check, it's free and easy. From a stop, Drop the gearshift in sport mode, bounce the gearshift selector one time backward to force second gear and hit the throttle.

BTW, I had 95,000 on my first set of plugs and currently running about 90,000 on my second. I only changed the first because I was there changing the valve cover gasket.

[AWSB328iM]

Originally Posted by rjahl

I'm not going to say that your plugs are fine but I would suggest just checking a second gear pull from a near stop. At one time, my car did the same thing at it was just slippery tires. The DSC would kick in and cut the engine power. It would then slowly bring the power back on. Doing a second gear take off from start will tell you if the engine is truly faulty or if the DSC trying to save you from yourself.

Why not check, it's free and easy. From a stop, Drop the gearshift in sport mode, bounce the gearshift selector one time backward to force second gear and hit the throttle.

BTW, I had 95,000 on my first set of plugs and currently running about 90,000 on my second. I only changed the first because I was there changing the valve cover gasket.

Early pre LCI N52 models have a 100k mile plug life. BMW changed the interval with LCI models to 60k. My car had symptoms before 60k. I bought it with 57,500 miles and I changed them at exactly 60,500 due to misfires accelerating from a low speed in a higher gear or if I floored the car it would also sometimes misfire even if I was in the correct gear. If I rolled on the throttle with light application no symptoms would show.

[rjahl]

Originally Posted by AWSB328iM

Early pre LCI N52 models have a 100k mile plug life. BMW changed the interval with LCI models to 60k. My car had symptoms before 60k. I bought it with 57,500 miles and I changed them at exactly 60,500 due to misfires accelerating from a low speed in a higher gear or if I floored the car it would also sometimes misfire even if I was in the correct gear. If I rolled on the throttle with light application no symptoms would show.

Ya, I cheated and logged mine. I could see the timing pulled back during the "event"

Most people don't realize that an Auto can really generate a crap load of torque through the converter. During take offs, the engine speed and turbine speed can be dramatically different and thus multiplying the torque by several factors.

Our cars fitted with pig leg rear ends can pretty easily loose traction. Many of rely on the DSC and traction control to keep us on the road.

Either way, the OP has two good suggestions and should know what to look for.

[2k11PDXE90]

Thanks AWSB328iM and rjahl Both of your responses are totally valid and make complete sense. The fact that I notice this more into turns than straights, it could very well be breaking loose. Though I have also noticed a rough idle on startup for the first few minutes, and sometimes the idle dropping lower than expected for a sec or two while standing at a stop light, which makes it feel like a plug is on it's way out. I'm a big believer of preventive maintenance so I will also order new plugs since I'm 4k miles away from the 60k mile maintenance mark. Thanks again for both of your responses!