Skip the auto shop - Our mechanics make house calls

Q: won't go over 40 mph

asked by on

Lets start off by saying this does not happen all the time but it is getting more frequent. We will drive the car straight for about an hour to an hour and a half. everything is fine and then all of a sudden the car will not go over 40 mph and struggles going up hill. I have had it to my mechanic 3 times for this problem. while they changed some things it has not changed the problem. Nothing they did worked. What could be wrong. I can't trust my car!

My car has 120000 miles.
My car has an automatic transmission.

This is a sign of a faulty throttle position sensor. This is a sensor that monitors the position of your foot on the gas pedal and relays this info to the car’s computer which then tells it how much fuel to introduce to the motor. When this is not working properly it will cause the car to go into limp mode occasionally, which is why the car wont go over 40mph. I would recommend having an expert from YourMechanic come to your home to diagnose your vehicle’s acceleration issue and replace your throttle position sensor.

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: Blown head gasket?

Hi, thanks for writing in. Unfortunately, white smoke in the exhaust, overheating and rough running all point to engine coolant getting into the combustion chamber. This is generally caused by a crack in the head or block or more commonly...

Q: Headlights come on when off in middle of night draining battery

There are several possibilities that may be the source of this issue - first make sure your headlight switch is in the "Off" position (rather than "Auto" for example). Then remove both the headlight relay and the daytime running light...

Q: 2015 Kia Forte Koup - Digital speedometer readout and voice recognition problems

Hello there, the 2015 Kia Forte is only equipped with the analog style speedometer and it is not possible to get both the analog signal and a digital readout. As for the voice recognition software, the inability for the system...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...