Q: Hesitation while accelerating while already moving, normal from a stop

asked by on February 28, 2017

Basically from the description above I'm just wanting to know what could be causing this delay in acceleration? I mostly notice if I'm slowing down like coming up on a yield sign then accelerating through. Hesitates then surges. More annoying than anything. And the car accelerates normal from a stop. Just purchased the car a week ago and still has a warranty so just wondering what I could be dealing with? Any words of wisdom are appreciated. Thanks

My car has 63000 miles.
My car has an automatic transmission.

Hi There, It sounds like you may have a fuel supply problem in getting the proper amount of fuel to the fuel injectors. As you know, when you turn the key to on, the fuel pump is activated and the fuel system is primed with fuel at a specific pressure in order to supply the fuel injectors with enough fuel to start the motor. When this is less than what is needed in order for the motor to fire or in some cases higher than normal, you may notice an erratic fluctuation in engine RPMs, hard starting or a lack of power when accelerating as the engine may be starved for fuel if insufficient fuel pressure exists in the fuel system. This can happen when the pump itself is not working properly or when the fuel pressure regulator is not maintaining the proper fuel pressure in the fuel system causing the engine to starve for fuel. This can also happen when there is insufficient connectivity to the fuel injectors which can cause an intermittent fuel spray pattern into the intake system resulting in a lean fuel condition or the motor otherwise starving for fuel. Lastly, I would also recommend checking the mass air flow sensor as this will also cause some hesitation at times when it is dirty or not working properly. A faulty oxygen sensor may also cause this type of behavior as well if not working properly or sending the incorrect signal to the computer. I would recommend having an expert from YourMechanic come to your location to diagnose your fuel system.

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Second Opinion] brake issues

Do you have a Audi Certified Mechanic?

Braking systems are practically uniform insofar as the technology across all models these days and specific model certification is substantially irrelevant for repair of this particular vehicle system. What is relevant is whether the mechanic you select actually follows service...

My key is stuck in ignition starts but won't turn back into lock position to remove the key.

The problem is most likely caused by a bad shift cable end not getting it all the way to the park position to allow key to turn all the way off. Have this cable checked at the transmission shift lever...

my 2005 cadillac escalade wont shift out of first gear what can be the problem

Hi there. Thanks for your email to YourMechanic.com's Ask a Mechanic. In most cases, when a transmission will not shift out of first gear, it is due to one of two things. First, and most common; is due to dirty...

Oil light goes off and on.

This light will usually come on when one of two things are happening. Either the motor is in fact low on oil or the oil pressure sending unit is not working properly and may be producing a faulty reading. I...

My automatic 2009 Jeep Wrangler shows 4 codes: P0562, P0306, C00377 & B2100.

Hi there, thanks for writing in. I would suggest replacing the battery first. A battery at 10V usually means one of the cells has failed. The P0306 code points out a misfire on cylinder 6. Since it is only one...

misfire and high idle when hot

You should have a compression test and cylinder leakage check done on the engine to see if one or more cylinders have low compression, or is leaking compression somewhere. Check that all of the spark plug wires and injector wires...

Related articles

How Long Does an Air Cleaner Temperature Sensor Last?
An An air cleaner temperature sensor is not overly common on newer vehicles. This is because in order to ensure that your car engine operates the way it should, several electronic sensors may actually be needed. However, if you drive...
A Buyer’s Guide to the 2012 Subaru Tribeca
This This 7-passenger SUV may have trouble keeping its head above water in the sea of competition, but its standard AWD, clean exterior lines and style-forward cockpit design make it an attractive choice in an increasingly crowded segment. Aside from...
How to Replace a Speed Timing Sensor
Some signs of a failed speed timing sensor include a Check Engine Light and poor performance. It's also known as the crankshaft position sensor.