Transmission jerk hesitation fix!

Hi guys, I am a long time BMW enthusiast, have been driving a 750i sport for some time now. I have done alot of reading about the hesitation and jerking that seems to happen to pretty much everyone. After trying many options, I decided to try cleaning the MAF, changing the MAFs has done wonders on an M5 I used to own. Long story short after cleaning the MAF with special MAF cleaner , and a que tip, I had put on approx. 8k miles, with no issues. Few days ago had it happen again, I figured Id give it another shot before buying a new one as they are not returnable. After cleaning again it drives great! I have ordered a new MAF and will be replacing mine, as it shouldn't need cleaning that often.

Posting this hoping it will help fix the issues many of you are having. It appears the MAF sensor can really screw things up in terms of oxygen distribution and thus causing these jolts and such. Whoever has these same problems should really give it a shot. Be careful when cleaning it make sure to be extra gentle, as its a sensitive part.

Hope to able to contribute to this board, and hang out here more often!

If you guys have any questions let me know Id be happy to help.

Forgot to add that MAF cleaner can be purchased at any hardware store, I got mine at PepBoys, shouldnt cost more than $5-8.

iceman, give us a little DIY, or some guidance on where to find the MAF in the car and how to remove and clean, thanks

Great post bro, welcome aboard.... we all love bimmers here.

Originally Posted by Tarek307

iceman, give us a little DIY, or some guidance on where to find the MAF in the car and how to remove and clean, thanks

+1 Yes indeed, a little guidance would be much appreciated. BTW - Welcome to the fest!!!

I cleaned mine today and I'll let you know how it turns out after a couple of days driving. I think the MAF sensor is located right in front of the engine block with the 2 air intakes meet and go into the engine. At least I hope I cleaned the right part.

Ok guys heres my attempt at a DIY.

Attached in the photo you will find the MAF (Mass Air Flow Sensor). To remove it there are two torx screws, one on top and one on the bottom.

Remove screws and pull out the MAF. There is a plastic covering that needs to be removed which is just held by clips, be careful removing them as they are easy to break.

Disconnect MAF by gently pushing on the release, do not apply any force, youll see the release right by the connector.

Make sure you let the MAF cool down, or better yet do it on a cold engine, because if you try cleaning it while it is still hot you can fry it.

Next step get some MAF Cleaner from Autozone or PepBoys, you can use other electric cleaners, but why when there is one designed specifically for this.

Take the can of MAF cleaner and spray all over the MAF up until the rubber gasket, make sure to not spray on the connector.

Take a que tip, and very CAREFULLY clean along the metal piece of the sensor.

After you are done give it some time to dry and reinstall. On the can of MAF cleaner it says dries instantly, but you really should give it at least 10-15 minutes to dry to be safe.

Hope this helps guys, good luck and let me know how it works out!

Here find a picture of the MAF, I found this picture online so this is a BMW MAF but will look a little different than ours. I included this picture so you can see where to clean with the que tip, and what the sensor should look like. This really is a simple, quick, and painless procedure. If this helps you will feel a difference immediately, and then you can go and buy a new MAF. I believe list price is around $325.

Seems to have also resolved any idle issues as well.

Hope this is all detailed enough for you guys, if you have any questions feel free to ask and Ill do my best.

I have read through alot on this forum and am happy to finally be able to contribute something.

1Bad540 , your car looks like my cars twin, minus the wheels. Where in NY are you? Im from Brooklyn myself, moved to NJ not long ago.

Originally Posted by jenkx

+1 Yes indeed, a little guidance would be much appreciated. BTW - Welcome to the fest!!!

Jenx your MAF would be different than his. Yours would be between the air filter and throttle body....it's the only thing between the air filter and the throttle body with wires coming out of it.

Just to clarify his problem. His issue is being caused by the mass air flow sensor giving incorrect readings to the DME on the amount of air entering the intake. This causes the fuel air and spark mixture used for combustion in the engine to be incorrect (too much air or too little air)... This is turn would cause a slight misfire causing the idle to fluctuate. What happens is that as the car is downshifting through the gears the idle fluctuates because of this slight misfire causing the car to jerk a bit when going into lower gears. This is because the DME is not able to adequately control the throttle input while down shifting. It's like if you were driving a manual shift and then you gave the car a little gas between shifting when it is in neutral and then slam it into gear. Those who drive a manual would clearly understand what gasing up between shifts would do.

Because the source of the problem is a slight misfire causing a fluctuating idle, anything that can cause a misfire can cause similar problems. In this case it was the MAF but it can easily be the spark plugs, coils, fuel injectors, vacuum leak or anything that can interfere with the fuel air spark ratio. Too much air is the fuel will cause you car to run "lean" and this is bad because it will run the engine hot. Too little air...there too much gas in the mixture will cause the car to rum "rich" which is actually cooler in the engine but the unburnt gas would make your exhaust smell and it would kill your catalytic converter in the long run.

Originally Posted by DFEL750I

Jenx your MAF would be different than his. Yours would be between the air filter and throttle body....it's the only thing between the air filter and the throttle body with wires coming out of it.

Just to clarify his problem. His issue is being caused by the mass air flow sensor giving incorrect readings to the DME on the amount of air entering the intake. This causes the fuel air and spark mixture used for combustion in the engine to be incorrect (too much air or too little air)... This is turn would cause a slight misfire causing the idle to fluctuate. What happens is that as the car is downshifting through the gears the idle fluctuates because of this slight misfire causing the car to jerk a bit when going into lower gears. This is because the DME is not able to adequately control the throttle input while down shifting. It's like if you were driving a manual shift and then you gave the car a little gas between shifting when it is in neutral and then slam it into gear. Those who drive a manual would clearly understand what gasing up between shifts would do.

Because the source of the problem is a slight misfire causing a fluctuating idle, anything that can cause a misfire can cause similar problems. In this case it was the MAF but it can easily be the spark plugs, coils, fuel injectors, vacuum leak or anything that can interfere with the fuel air spark ratio. Too much air is the fuel will cause you car to run "lean" and this is bad because it will run the engine hot. Too little air...there too much gas in the mixture will cause the car to rum "rich" which is actually cooler in the engine but the unburnt gas would make your exhaust smell and it would kill your catalytic converter in the long run.

Excellent info!!!

Welcome to the FEST!

Nice info there. Although I believe the "infamous transmission slam" I experienced (and probably most) is directly related to the tranny itself. Which I got replaced under warranty.
But back to MAF sensor. This is interesting. Damn that thing looks like a paper clip! Hate when dainty things are used for such large/crucial tasks.

Hey, the same fix used to work on my 03 Chevy Tahoe!!! Just make sure you use MAF Cleaner or Circuit Board cleaner. I've heard of people trying to Use Carb cleaner and having to buy a new MAF.

I am from Bk(Brooklyn)my self just recently move to Cali.

You need a security 5 point torx screwdriver. I just removed both ends of the air intake a slipped the maf section of the tube out, cleaned the maf and replaced it all as auto zone didn't have the 5 point screwdrivers. btw even at 80k my maf looked brand new.

Thanks for the welcome guys. Tx I don't think this the solution to all transmission issues, but I think it has a lot to do with many diff things that affect transmission smoothness, and that hiccup in acceleration at light throttle. This is my observation after having done fuel filter, , reset and such. All had no results until the maf.

Has anyone tried it and had any positive results? Really hoping this works for you guys. Before doing this the other day, the car was running so weird jerking at every shift I felt like I wanted to dump the car off a cliff it was that annoying.

Rookie where in bk?

Canarsie Between Flatlands & Glenwood

Originally Posted by iceman28o1

I cleaned mine today and I'll let you know how it turns out after a couple of days driving. I think the MAF sensor is located right in front of the engine block with the 2 air intakes meet and go into the engine. At least I hope I cleaned the right part.

Update???

I have started to wonder about cleaning mine.
But I would like to hear more from folks who have:

When and why did you?
Noticeable improvements?
What exact cleaner did you use?

It's a very sensetive and expensive item. Don't want to jack with it of not totally necessary.


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Originally Posted by TXSTYLE

Update???

I have started to wonder about cleaning mine.
But I would like to hear more from folks who have:

When and why did you?
Noticeable improvements?
What exact cleaner did you use?

It's a very sensetive and expensive item. Don't want to jack with it of not totally necessary.


GALAXY Tab ~ Powered by ANDROID!

GALAXY Tab ~ Powered by ANDROID!

Tex if your car is running smoothly i wouldnt do it, epecilly since u got ur tranny replaced.

Okay thanks for this thread fellas.
So i had my engine light come on and the error code is: P2187 (system too lean at idle bank 1) and P2187 (system too lean at idle bank 2) Failed MAF
Probable cause(s) Low fuel pressure, vacuum leak on engine, failed h02s (heated oxygen sensor)

Do you guys think cleaning this MAF sensor would resolve my issue or i need to replace it?

nice info thanks really useful

Okay thanks for this thread fellas.
So i had my engine light come on and the error code is: P2187 (system too lean at idle bank 1) and P2187 (system too lean at idle bank 2) Failed MAF
Probable cause(s) Low fuel pressure, vacuum leak on engine, failed h02s (heated oxygen sensor)

Do you guys think cleaning this MAF sensor would resolve my issue or i need to replace it?

it happen to me same error code, all I need to replaced Pressure Regulator Valve you can get it from http://www.ecstuning.com/BMW-E66-745...ion/ES2091226/

Gonna try it this weekend

Originally Posted by wicky

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Put one up then man!