2003 X5 stalled while driving at low speed
 

Well car has just about 233k. Engine is strong and I'm not ready to give up on her, but she stalled now 3 times while driving at low speed and it's scary. Braking is odd bc no vacuum. Need to stop and move to park and it restarts. 1st time it happened 8k miles ago, but it recently happened 100 miles ago, twice in about 2 minutes. Then the car ran for an hour no issues and I've parked it.

Here are some recent service things done. Swapped dead fuel pump with my other car which was a 2006 with 80k miles. I only swapped the pump, not the float and housing. At the same time I also put in new crankshaft sensor. After these two items, about 1k miles that is when the car first stalled at low speed. It didn't happen again for like 8k miles. Before it happened again, I recently changed both camshaft sensors, fuel filter and oil change. After this work, car stalled twice as I said.

No codes, no errors. Car starts right up. Could be in my head but I feel like the start up makes a little extra hesitation on the crank, just an extra second or so. Really don't know what to do now. Engine is strong, good compression. Hate to give up.

Spark plugs can do that. You should still have some vacuum for braking after engine stalls unless the check valve isn't holding or the booster is shot. So your foot is off the gas when stalling happens ?

2003 X5 stalled while driving at low speed
 

Speed while driving? Driving under power or coasting?

Are the cam/crank sensors OEM or better?

To add to the confusion I had similar with a dodgy MAF. Did not pop codes at the time.

Edit: the stalling, not the brakes.

For the brakes I experienced similar on an N42 engine, it was a combination of a weak vacuum pump on head and faulty one way valve to booster.

You're onto something with the vacuum link.

You should get 3-4 brakes applications after the engine stalls.

If not, there's definitely a problem with vacuum retention.


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Rapping on the MAF often works to weed out those ones.

Agreed, check for MAF problems with tap on MAF with screwdriver plastic handle.


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If fuel level < 1/4...maybe it is the infamous O-ring ?

Facts: good call. What's the fuel level?


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Hi, fuel tank is generally more than half full. My brakes work good and what I mean is that the brakes are not normal when the car shuts off. Yes I can brake and stop the car, but it's not really safe... Car was smoke tested so it's not a typical vac leak. I've dealt with that and usually has codes or engine misfires. None of that here. The stalls happened in traffic so low speed, like under 5 mph and likely foot off the gas coasting in traffic. I'm leaning toward replace fuel pump and housing, also swapping in a new MAF which I replaced maybe 5 years ago.