BMW E87 116i/118i petrol engine hesitation
Why does my E87 116i (N45) hesitate or run poorly when cold?
Common causes are the ignition coils, which are a known weak point on this engine, and an intake leak. The timing end can also be the cause, and the problem can persist even after the timing chain tensioner has been replaced. Start with the coils and the intake, and if the fault continues, have the timing end checked.
What causes uneven running and misfire codes on the N46 engine?
On the N46 the cause can be in the Valvetronic system. The Valvetronic spring in the valve cover can break, which makes the engine run on three cylinders and the codes point to one cylinder. A worn Valvetronic cam and lifters can also cause an uneven idle.
What should be done about hesitation when the fault code points to Vanos control?
Vanos is the camshaft timing adjustment. Replace the exhaust cam Vanos solenoid (control valve) first. If the fault continues, the cause can be the O-ring inside the cam, the cam housing or a blocked oil passage, and this is workshop work.