Skip the auto shop - Our mechanics make house calls

Q: rough idle on start up everytime

asked by on

2003 BMW 318i 2.0. Car would take 3-4 tries to start up and then immediately stall if i didn't keep the revs consistent and between 1 and 2.5k. There would be loss in power while driving.

Parts changed to try and cure (btw no EML light and nothing on diagnostics):

  • EXH and INLT camshaft sensors
  • EXH and INLT solenoids
  • Timing chain tensioner (old one was 5mm shorter)
  • Full service

Timing chain was inspected with rocker cover off - was fine Car has only covered a genuine 58k miles

Rocker cover gasket was replaced about a year and a half ago due to smoke coming out of where the EXH manifold but this problem is still present whenever the car starts up.

All parts are from BMW dealer so this problem has cost me a lot so far.

So after these parts replaced. The car starts up first time but again have to keep revs over 1k otherwise it will stall. After keeping revs consistent and letting the car warm up for 10 minutes. The idling levels normally and then it drives fine with no fault.

My car has 58020 miles.
My car has an automatic transmission.

You could have several things contributing to the hard start. Dirty or faulty throttle valve, idle air control valve, bad temperature sensor, and more. I suggest having a certified technician, like one from YourMechanic, perform a few tests to be able to diagnose the exact cause of your stalling issue.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Sensor under intake manifold

Hi there, thanks for writing in about your 1993 Honda Civic del Sol. Your friend was probably referring to a failed MAP sensor. It does reside under the intake manifold and can cause mixture issues resulting in RPM surges. One...

Q: Is it my motor mount

Hello. Unfortunately a bad engine mount will not cause this. Most of the time this is caused by a bad crankshaft position sensor or a failing fuel pump. Most of the time when it just cuts off like this it...

Q: Cranks but doesn't start and also I don't see the rpm move when I try to start, what should I do? - 2002 Nissan Altima

Hello - I suspect your crankshaft position sensorhas failed. This sensor provides the ignition system with timing information - when to fire each spark plug. This sensor is also the trigger for the tachometer, since it is counting engine revolutions...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.