BMW 135i N54 engine common faults
135i
E82 135i accelerates in steps and gives misfire faults, what is the cause?
A misfire is most often caused by an ignition coil, next by a spark plug and less often by the injectors or the lambda sensor. A new coil has cured the fault. Also check the condition of the spark plug, because it can reveal a leaking injector.
E82 135i rough idle and deposits in the intake ports?
Dirt builds up in the intake ports and on the valve stems, and the deposits usually cause a rough idle. There can be deposits already at around 50,000 km. Cleaning is done by walnut shell blasting, and it requires removing the intake manifold (about 2–3 h).
E82 135i wastegate rattle at idle, what causes it?
The wastegate shafts wear loose, so the flap does not seat properly and a rattle starts at idle. Opinions differ on the effect of a software update, because the fault is physical. Have a workshop check the situation.
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