Skip the auto shop - Our mechanics make house calls

Q: Hesitation at RPMs lower than 2000

asked by on

My vehicle has hesitation problems at RPMs lower than 2000. While driving and accelerating up to 2000 RPM, this problem occurs. It seems like it doesn't get enough fuel or air. This is not such a big deal when the engine is cold. The car drives well at RPMs higher than 1700. I had a fuel filter and air filter replaced. Also, the MAF sensor and fuel injectors were cleaned. There are no error codes appearing. Several mechanics ran diagnostics and cannot find the reason for this and the hesitation issue persists. Can you give me some advice? Thank you.

A: The vehicle may have unmetered air entering...

The vehicle may have unmetered air entering the engine, which is air entering the tubes between the mass airflow sensor and the throttle body. If there are no leaks, then the fuel trims in the data would need to be inspected, to determine if the two front O2 sensors would need to be replaced with the new part number. The O2 sensors give fuel control feed back to the ECM and if the system is too lean you will get a part throttle hesitation. The technical bulletin is 03-09-11 and the new part number to replace the O2 sensors is 3S4Z-9F472-BA. This part may have been updated since the bulletin. If you need to get your O2 sensors replaced, consider a certified mechanic, such as one from YourMechanic to come to your home or office to replace your O2 sensors.

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・Fair and transparent pricing

Get a quote

What others are asking

Q: 2011 impala speedometer up & down while idling, car cuts off at low lidle

I think you mean that the tachometer is going up and down, not the speedometer. If the tachometer is going up and down and then the engine stalls, it's an indication that the engine has a major vacuum leak...

Q: Difficulty shifting on cold start, shakes upon acceleration

Hello. Thanks for writing in about your 2010 Ford Transit Connect. Most of the time, if the vehicle has low miles on it, this is caused by a programming issue. I have had a lot of these come by with...

Q: Car will start and run smoothly but will die when you try to accelerate.

Hi there. There may be a misfire on a cylinder that is causing the engine to hesitate on acceleration. Check all of the spark plugs and wires and see if they have burn marks. If there is burn marks on...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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.