Q: When the car hits 40 mph it feels like it wants to stall and slow down.

asked by on

Check engine light not working. Cranks slow. When driving up hill looses speed, reaches 40 mph and wants to slow down. Once it goes under 35 mph it picks back up. It looses speed even on flat ground at 40. I have changed fuel pressure regulator and a throttle sensor. Seemed to get worse after changing throttle sensor.

My car has 200000 miles.
My car has an automatic transmission.

This is a sign of a potentially failing or dirty mass air flow sensor. This is a unit that regulates the air intake into your engine and ensures that proper air/fuel mix is injected into the engine. When this is dirty or not working properly, this will cause an intermittent delay or lack of acceleration as you describe. To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your home to take a look at the vehicle and properly diagnose your loss of power.

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
  1. Home
  2. Questions
  3. When the car hits 40 mph it feels like it wants to stall and slow down.

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: Q: Car shut off while driving

Without additional information, it is hard to say what could have caused this. Your car has a variety of sensors that can cause it to shut down depending on whether or not everything is functioning correctly. I would suggest having...

Q: I have a 2003 lincoln navigator.The drivers fornt door power window does not work. I replaced the regulator, main switch and motor

If the other 3 windows function using their individual door switches but there is no function, for any of the windows using the main driver door switch console, that could be due to the wiring in the driver door having...

Q: The car is not accelerating right and the speedometer is jumping.

Hello. The speed info goes from the VSS (vehicle speed sensor (transmission output sensor)) mounted on the tranny, to the PCM (powertrain control module (computer)) mounted on the passenger firewall, to the dash speedometer. If the speedometer is not functioning...

Related articles

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...
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...
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.