Recently I have encountered an issue. Whenever I start my car up it shakes very vigorously; in addition, whenever I try to accelerate the RPMs drop and it struggles to get up to speed, and occasionally it shuts off when I come to a stop and attempt to accelerate. When we first purchased the vehicle we replaced the belts thermostat water pump gave it an oil change. My thoughts are that it is the camshaft position sensor.
We also have a OBDII scanner and the following codes were present: 7B  signal, characteristic map cooling, short circuit to positive F1  misfire, cylinder4, misfiring during warmup, worsening emissions (misfire CARB_B1) BE  Data-filing differnece to central light module 1E  AUC Heating
We were also curious of the possiblity that the temperature sensor needs replaced, but we doubt it because the temperature in the car always stays consistenly in the middle. Could it be a bad coil?
My car has 2500000 miles.
My car has an automatic transmission.
Ignition coils are real suspect in this engine, especially if they are the original Bremmi coils. BMW has posted service bulletins concerning coil issues. Camshaft sensor, possibly but generally if camshaft position cannot be determined of varies too greatly from crankshaft position, then a fault will be logged. Even if the VANOS system is having issues adjusting cam timing faults will generally be logged. Since there is a hard misfire fault on cylinder 4 one strategy might be to move the spark plug, ignition coil, and fuel injector from cylinder 4 to other know good cylinders to see if the misfire moves to another cylinder. This will point towards the failed component. The thermostat fault probably does not have a direct link to the stalling issue but if the fault is present then this indicates a problem with the MAP thermostat. The plastic tangs that hold the thermostat element into place can break and cause issues with the cooling system. This is another thing that you may want to have looked at as well. These issues will require in-person diagnosis, including the diagnosing of the stalling issue, and the thermostat. YourMechanic would be happy come to your home or office to properly address these issues.
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