Q: My car idles very roughly on first start up of the day

asked by on

Every day on the first engine start up of the day my car idles very roughly as if the engine is about to die and the Rpms start to jump. This used to happen very badly only when it's cold outside, but now it's starting to happen also when it's not cold. To make the very rough idleing stop I have to press the gas lightly until the engine heats up and then it's all good. Once the engine is heated the car drives very good. Very smooth. I have been getting lean fuel mixture codes and misfire codes. I Don't know if this is a bad coil pack or something else. I also recently changed the spark plugs.

My car has 123000 miles.
My car has an automatic transmission.

The lean fuel mixture codes may explain everything. They frequently occur when there is an air leak in the intake system somewhere. Your engine has an Air Flow Meter (MAF) that measures the air going into the engine. The ECU uses this information to decide how much fuel to inject. If there is an air leak, or of the MAF is bad or dirty, air will get into the engine without being measured and so there won’t be enough fuel delivered. This will lead to poor idle and misfires. You can check under the hood for damaged or poorly connected hoses or air boots, but if you need some help with this you can contact Your Mechanic. They will send a technician to your home or office to check out your BMW and tell you what it’s going to take to solve your problem.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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!
  1. Home
  2. Questions
  3. My car idles very roughly on first start up of the day

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: i put an cold air intake on my 2014 bmw 328. now my my car some times idles really high and even cuts off.

If you want to return the car to stock, you can obtain the broken part by using the used parts database at Car-part.com. If your desire is to see if you can get the cold air intake to work with...

Q: if my car takes 4-5 sec to start is it the fuel pump?

Hello, thank you for writing in. A weak fuel pump is a great place to start. If the pump was failing, you may also experience issues while driving. If the fuel system is not keeping fuel available to the engine...

Q: Q: VALVE Cover GASKET Replacement

Hi there. Assuming, the valve cover gasket was properly replaced. The smoking under the hood, may have been residual oil burning off the exhaust manifold. The white smoke seen coming through the grill, may have been the snow turning to...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...