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Bryan, BMW Technician
Category: BMW
Satisfied Customers: 410
Experience:  Background in electrical and drivibilty diagnostics Expert in oe scan tools and diagnostics
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2006 X5 3.0: I have X5 2006 3.0 .. Acceleration problem

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I have X5 2006 3.0 .. Done 85k only. Doing service regularly. Few month ago after 80Km service car is not accelerating above 100km. As if stuck there .. Below 100km I notice some delay between gas and response. any idea? No error codes and the mechanics claims that he could not find anything wrong. He claims that he checked MAF sensor and filters but no problem. The feeling as if the gear is not shifting after speed 100 km ..

Hello Im Bryan I will try and answer your question.


Mass air flow sensor can cause this problem, but unlikely

This could either be a transmission related issue or a engine issue

Does the vehicle hesitate or act as there is a misfire at the speed you mentioned?

Does the vehicle hit a specific RPM range where this occurs and can you get this issue to happen with the vehicle parked.

This could be caused by clogged catalytic converters or from a fuel pump going out I need some more information to answer your question.

Customer: replied 3 years ago.
Hi Brian,

As I said, my experienced mechanics says no error codes. He said he tried to replace MAF sensor with another one for testing but did not help. The MAF he used was not new.

Yes it hesitates but if I keep pushing gas moderately it will go above hundred but slowly with delay. Generally speaking I feel delay in response even below speed 100k.

When this happen I think RPM will be around middle I mean 12 clock direction almost. I did not try when parked. How to try that? Also fuel pump was replaced almost a year ago.

This sounds like a mass air flow sensor or a fuel pump, to determine which one, I would purchase a can of Mass air flow cleaner and spray your mass air flow sensor and then asap test drive the vehicle. If no change is seen I would be looking at the fuel pump.

If your mechanic has a scan tool that can look at live data when this is happening have him check the PID blocks for fuel trim if the vehicle goes rich the problem is not in the fuel pump its in the mass air flow sensor, if the vehicle goes lean it could be either the mass air flow sensor or the fuel pump. But like I said this sounds like a mass air flow sensor.

Being the fuel pump was recently replaced I do have one question was the fuel filter replaced with it. a clogged fuel filter can cause this issue also

Customer: replied 3 years ago.
Yes Fuel filter was replaced few months ago together with other moving parts at 80K. Honestly problems observed slightly after that. Not immediately but may be few weeks after. Is it because parts were defective or not original? I have no way to tell as I do not know what the local mechanics did.

Mechanics claimed that he put another MAF sensor (used one) to test but there was no change. What drives me crazy is that my mechanic is one of the experts in the town nevertheless he claims that he could not find the problem after leaving the car 5 days at workshop.

What do you suggest?

Another observation which might or might not be related is that the power steering (which is actually not great in X5 3.0) is becoming more hard although that mechanic replace oil and something else.

Is there any way I can send u now a copy of what was replaced in the service by email ?
(Edited by Moderator)

I would try cleaning the mass air flow sensor which is easy

just remove the air filter box spray the cleaner on the sensor and reinstall then test drive vehicle asap and see if problems is gone if is then replace the mass air flow sensor


Testing with a used sensor is useless his sensor could be just as bad as yours.

Customer: replied 3 years ago.
Ok will email you shortly.

So to summarize the steps ..

1) clean MAF sensor
2) replace with another fuel filter assuming the last one is defective
3) replace maf sensor
4) replace fuel filter

Anything else?

Start here

With the vehicle on but the engine off press the gas pedal to the floor for 1 min this reset all adaptations.


Clean mass air flow sensor and replace air filter if needed

Next yes replace fuel filter if problem still present

last would be having the vehicle diagnosed for either bad mass air flow or bad fuel pump

this is not that hard with a scan tool you can read the computer and see what the mass air flow is reporting if it is reading 100kgh then drops to 40 when the problem occurs there is your issue.

Other than that a fuel pressure test will tell you if your pump and filter are working correctly

Customer: replied 3 years ago.
Great, just scan the email I sent u now and let me know if anything else need to be done.
The crankcase gasket ? this could cause the issue if it was leaking it could lean out the engine so much that the vehicle would misfire and not run real well
Customer: replied 3 years ago.
Many thx

Will the above chat thread be sent to me now when I rate the case ?

I believe so

The crankcase gasket is confusing Im not sure which gasket they are refrerring to but if its leaking air into the crankcase the result will be the engine runs lean

Lean makes more power but if to much air gets in the engine will misfire and the vehicle will seem sluggish

Bryan and 3 other BMW Specialists are ready to help you
Customer: replied 3 years ago.
Hi are you online?
yes I am