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k.olson 5/23/2019

2009 BMW 535i xDrive Base 6 Cyl 3.00L


hesitation, rough idol, limp mode loss of power

I have 150,xxx on car. car starts. it has no problem rev-ing when i push the gas while in park. once I shift to drive, I get a rough idol that sounds deeper that it does when in park, like it is going to die. I then try go drive and when i hot about 5mph it goes into limp mode and has no reaction if I press the gas. If I then stop and put it in park, the car responses again and will rev up. I have cleaned the vanos, I have replaced plugs, both fuel pumps and sender unit, I have replaced valve cover and seal, I have walnut blasted the manifold, I do have injectors that do leak but not that bad, I have replaced coils, and just did water pump and thermostat.

1 Answer


Jimm 9/19/2019

First step - have the stored fault codes or check engine light scanned - for free - at any local auto parts store; Advance Auto, Auto Zone, NAPA.
Then, post a reply as 'add answer' with the specific code for more assistance.

This aspect is important; there may be a fault code stored in the OBD memory which may not be displayed as a check engine light.

Do not skip this important first step - there are literally hundreds of possible fault codes. Avoid wasting/ throwing money at the problem.

Possible Causes of Engine Hesitation or Stumble:

Dirty,leaking fuel injectors (cleaning the injectors often fixes this)
Dirty air filter (change filter)
Dirty / clogged fuel filter (change filter)
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires


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