Skip the auto shop - Our mechanics make house calls

Q: Misfires at high speed on a high way

asked by on

The car moves smoothly at high speed up to 100miles per hour, but when I push the pedal down (kick down) to overtake other vehicles the engine misfires, showing check engine light. When l reduce speed a little, the engine regained full power and the check engine light disappears from the dashboard. Best regard.

My car has 100000 miles.
My car has an automatic transmission.

A: Hello there, a few common faults will cause...

Hello there, a few common faults will cause your 2004 BMW 540i to have a misfire on acceleration. Without knowing what code the engine is storing I can only offer general advice. Likely causes for the car to misfire like this would be the fuel pump, fuel filter, spark plugs, coil pack, throttle body faults, or a wiring harness issue. Since the problem only occurs when the pedal is pressed at first this tells us a part is on its way to failing, but has not fully yet. A qualified Technician such as one from YourMechanic will be able to diagnose your misfire condition and make any repairs required to resolve the 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・Save up to 30%

Get a quote

What others are asking

Q: Is it worth fixing

Hi there, thanks for writing in about your 2000 Cadillac Escalade. If you overheated the engine until it died, then you may have damaged the engine internally on cylinder number 4. Your water pump is most likely the part leaking....

Q: Car accelarates to 3000 rpm in park or neutral.

The throttle position sensor (TPS) is most likely failing. Air leaks in the intake can also generate a high idle, but not usually this high. If you need to have this checked, have a local mechanic, like one from YourMechanic,...

Q: Grinding noise when ABS engages brakes

The most likely cause of this issue would be a failed hub assembly or failed wheel speed sensor. The grinding sound you hear could possibly be a dry spot in your wheel bearing, or just the buzz that is...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
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.