Car seems to hesitate when stepping on gas at low speeds

CHEVYOWNER10

MEMBER
2010 CHEVROLET AVEO
1.6L
4 CYL
2WD
AUTOMATIC
76,000 MILES

My car jerks and hesitates for a couple seconds when I put my foot on the gas to accelerate during low speeds. As soon as I step on the gas after a stop it's when you feel the engine hesitate like it's resisting for seconds then it's fine.

Spark plugs are not that old, it doesn't even have five thousand miles on them yet.
Air filter could be slightly dirty but not clogged to the extent the car doesn't accelerate smoothly.
Mass air flow sensor was checked, and I cleaned
Throttle position sensor was replaced
Coolant temperature sensor was replaced
Fuel filter on this car isn't serviceable until the fuel pump is replaced and I am getting fine fuel pressure.
Coil packs would be an issue if the car were misfiring badly or code set.

I am thinking a bad ignition module or dirty fuel injectors. Do you recommend using a fuel additive to clean the fuel injectors? Or can I check the ignition module? Where can it be located on this vehicle? Is it hard to get too to check with a multimeter?

9 Replies

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Hi,

It could be related to dirty injectors or even the throttle body needing to be cleaned. As far as the injectors are concerned, it wouldn't hurt to try a quality fuel injector cleaner that mixes with the fuel. The throttle body can be serviced as well. Here is a link that explains how it's done:

https://www.2carpros.com/articles/throttle-actuator-service

I do have a question. By chance do you have a scan tool that can provide live data? If you do, could you let me know the short-term fuel trims?

Let me know.

Joe

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Tuesday, May 3rd, 2022 AT 8:05 PM

CHEVYOWNER10

MEMBER
93 POSTS

I will try the fuel injector cleaning and see if the throttle body needs cleaning. I do have a scanner that provides short term and long-term fuel trims. I will take a look at the readings and let you know if they seem to be normal.

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Wednesday, May 4th, 2022 AT 8:55 PM

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Hi,

Sounds like a plan. Before performing the service, check the fuel trims. I don't what them to change due to something being serviced because then I won't know if that is the actual problem.

Let me know.

Take care,

Joe

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Thursday, May 5th, 2022 AT 6:29 PM

CHEVYOWNER10

MEMBER
93 POSTS

Okay, I haven’t done any fuel service treatment yet or clean throttle body.

What I noticed while driving today was at idle it just stays lean in long term fuel trims at idle and when you are accelerating it gets rich but not real rich, just stays as far as between 5%-9% at accel. But one time randomly while accelerating it moved from rich to lean and it started to run really lean until it went back to rich again at accel. It went from 5% rich to -17% lean then went back to rich again but wasn’t dumping a lot of fuel back.

At idle or coming to a stop and idling it always goes back to lean and never stays at rich. Short term fuel trims are good. I don’t see any abnormal readings or out of range readings. All I see is the long-term trims that concern me as it’s always lean at idle and rich at accel and does not ever stay stable as it should. Normal readings would be when it moves to lean to rich and keeps moving back and forth like stable fuel trim numbers should be. Ya know lean to rich, lean too rich. Usually when it falls to 0% you know it’s at a really good range.

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Sunday, May 8th, 2022 AT 11:15 AM

JACOBANDNICKOLAS

MECHANIC
109,896 POSTS

Hi,

In a perfect world, STFT of 0% is perfect. However, they do jump around. The 5% is normal, but the -17% is high. The -17 indicates the computer is trying to lean the mixture. What is considered normal is if they stay between -10% and +10%.

Does that make sense? LOL I can never tell if what I write will be understood.

Let me know.

Joe