car stalling and very sluggish

[troyounces]

Hello everyone,

I have a 2001 X5 3.0L. Two weeks ago my car stalled while driving in a parking lot at very low speed. I restarted it and had a check engine light. When I tried to accelerate the car gently (from stop) it would stall on me. When I accelerated harder the rpms would drop suddenly but the car would not stall. When driving the car felt like it weighed 10 tonnes and was having trouble accelerating. The next morning, I started it up and it ran fine.

The problem happened again a few days later. After reading a few threads I decided to change the Mass Airflow Filter. I thought it worked but it happened again yesterday. It seems that starting the car on a hot day, when the engine is already warm causes this - although it could be a coincidence, but this has been the case every single time.

I ran carsoft (which I just bought yesterday) and it said there is a problem with my oxygen sensor post catalytic. From what I have read, this would not cause these problems.

My guess is that there is a problem with the air/fuel mixture. Does anyone have any ideas what else I can check?

Thanks again.

[sunny5280]

Originally Posted by troyounces

Hello everyone,

I have a 2001 X5 3.0L. Two weeks ago my car stalled while driving in a parking lot at very low speed. I restarted it and had a check engine light. When I tried to accelerate the car gently (from stop) it would stall on me. When I accelerated harder the rpms would drop suddenly but the car would not stall. When driving the car felt like it weighed 10 tonnes and was having trouble accelerating. The next morning, I started it up and it ran fine.

The problem happened again a few days later. After reading a few threads I decided to change the Mass Airflow Filter. I thought it worked but it happened again yesterday. It seems that starting the car on a hot day, when the engine is already warm causes this - although it could be a coincidence, but this has been the case every single time.

I ran carsoft (which I just bought yesterday) and it said there is a problem with my oxygen sensor post catalytic. From what I have read, this would not cause these problems.

My guess is that there is a problem with the air/fuel mixture. Does anyone have any ideas what else I can check?

I assume you meant Mass Air Flow Sensor (to my knowledge there is no Mass Air Filter).

One thing you might try is to disconnect the MAF. Doing so causes the system to use fail-safe parameters for the air/fuel mixture. If the stalling / stumbling disappears it would indicate a problem with the MAF (unlikely since you just replaced it) or a leak in the intake post MAF. You may have created an air leak where the intake boot connects to the engine when you replaced the MAF.

[Weasel]

Another possibility would be the intake cam position sensor dropping signal, and it doesn't throw a code for it right away but will after a few days.

[troyounces]

Yes - you are right. I replaced the Mass Airflow Sensor - not the filter.

The next time it happens I will try disconnecting it and see what happens. Should I have replaced the rubber gasket that sits on the MAF?

[sunny5280]

Originally Posted by troyounces

Yes - you are right. I replaced the Mass Airflow Sensor - not the filter.

The next time it happens I will try disconnecting it and see what happens. Should I have replaced the rubber gasket that sits on the MAF?

Unless it showed some kind of excessive wear or was torn I don't think it would be necessary.

[troyounces]

Ok, I just drove it all day and ran carsoft. Here is what I get:

228 Mixture Deviation: bank 2
Cylinder 4-6

65 Camshaft angle pulse generator

I'm guessing the camshaft position sensor needs replacement. Would that also cause the Mixture deviation error? Or could something else be causing this problem?

Also where is the camshaft angle pulse generator?

[Weasel]

Depends on which cam sensor it is talking about... The exhaust cam position sensor is on the left side of the front of the head and the intake cam position sensor is on the intake side of the front of the head, right by the vanos oil line and solenoid.

[troyounces]

Thanks for the reply.

It doesn't look like there is any way to determine which one it is based on that error code. Is it possible that this error is not even caused by any of these sensors? Something like a vacuum leak?

[Weasel]

The camshaft angle pulse generator fault is definitely from a cam position sensor... but without a better fault description on which it is you don't know which. Odds are from the symptoms it is the intake cam sensor, but as easy as the exhaust cam sensor is to change it isn't a bad idea to just change both of them anyways.

[troyounces]

Thank you very much. I'll replace it tomorrow and report on how it goes.