Q: Bmw will not go over 20 mph

asked by on August 09, 2017

My BMW will not go over 20 mph it happened last week while driving it automatically kicked down into a lower shift and I almost got ran off the road. A week later it's sitting in the garage with high rpm and still won't go past 20 mph when parked
My car has an automatic transmission.

This may be a sign of a vacuum leak. High idle speeds or in some cases rough idle, stalling and hissing sounds are common signs of a vacuum leak. When a vacuum leak is present in an engine, this causes an excessive imbalance in the air/fuel ratio which creates a loss of power and causes the motor to run at a much higher RPM as a result of the increased oxygen present in the fuel charge being injected into the motor. This may also be caused by an idle control valve that may be sticking or failed due to old age or deterioration. I would recommend having an expert from YourMechanic come to your location to diagnose your vacuum leak as these can be very difficult and time consuming to trace.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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

Head gasket or not?

If it is confirmed (i.e., no false positive) that exhaust gas is present in the coolant, that means one of three things: the head gasket is leaking, the head has a crack in it (not unusual) or the block is...

Stiff steering wheel and gas pedal, engine shudder

Hello. The power steering pump, power steering lines, and/or steering gear could be faulty or have a leak. The problem you are having with your accelerator pedal being hard to press could be due to a throttle cable that is...

335d p20ee code, SCR metering valve cleaning

The valve is accessible but testing, which is performed coincident to cleaning, requires a BMW specific bi-directional scan tool. The scan tool is used to remotely actuate the valve to see if it is even working. There are other causes...

Related articles

A Buyer’s Guide to the 2007 Ford Crown Victoria
This This enduring Ford classic enjoyed a nearly two-decade run before being discontinued from the retail market with the 2007 model-year being the last. Ever-popular with law enforcement (for whom models continued in production through 2011), and senior citizens, the...
A Buyer’s Guide to the 2012 BMW X5
The The 2012 BMW X5 is an SUV that offers both utility and ease of driving. The steering is responsive with a good amount of horsepower. If you are looking for a sportier SUV that offers versatility, the BMW X5...
A Buyer’s Guide to the 2012 BMW 1-Series
The The 2012 BMW 1-Series, which includes both the 128i and the 135i in both a coupe and convertible options, provides the perfect combination of power, performance and luxury. Designed with a focus on thrilling acceleration and a smooth, elegant...