Skip the auto shop - Our mechanics make house calls

Q: Vehicle slows down slightly then speed up slightly while driving.

asked by on

Vehicle slows down slightly then speed up slightly while driving. Also when starting from a stop, the vehicle starts to move then slows up slightly then you have to apply more accelerator to get the vehicle to continue to accelerate. The vehicle does not do this at high speeds or is not as noticeable at 70MPH or above.

My car has 49000 miles.
My car has an automatic transmission.

This may be a result of low transmission fluid or potentially a faulty transmission control module. A faulty transmission control module may cause a delay in acceleration or erratic shifting of gears. The transmission control module has various sensors such as vehicle speed sensors, wheel speed sensors, throttle position sensors, turbine speed sensor, and transmission fluid temperature sensors that all direct information to it in order for it to perform it’s function. Other functions controlled by the TCM are components such as a kick down switch, traction control system, and cruise control module. Any of these may also affect the way the transmission control module performs and controls the transmission and the shifting of your vehicle. I would suggest having a professional from Your Mechanic come to your location to properly diagnose your transmission problem.

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

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: How do I use the turn signals?

The turn signals are important safety features that alert your surrounding drivers of your intention to make a turn. To signal a right turn, pull up on the turn signal lever (located on the left side of the steering column),...

Q: Car will not turn over - 2011 GMC Acadia

A flashing Check Engine Light is commonly an indicator that you have non-burning raw fuel that is flowing into the exhaust system or triggering the O2 sensors to report this information. This is one reason why your engine is probably...

Q: Bleeding Breaks/hubs

Hi there. Without being there to physically inspect your Alero, the best advice we can offer is to send you to this article on how to bleed car brakes. You might want to purchase a service manual for the vehicle...

Related articles

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...
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...
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.