Code 303 cylinder 3 misfiring, check engine lights on, airbag and traction control lights are on

Tiny
JENN LYNN
  • MEMBER
  • 2011 CHEVROLET SILVERADO
  • 4.3L
  • V6
  • AUTOMATIC
  • 130,837 MILES
My truck has been acting up; sputtering not wanting to take off right. I went to go get it checked at AutoZone and they ran the codes and it was 303 cylinder 3 misfiring. My check engine lights on, my traction controls on, my stabilizer for tires is on. Airbag light is on. Now it is worse I want to stay running doesn't want to take off. Change the spark plug and it was burnt and it's worst. Sprayed the intake. Q
Friday, June 25th, 2021 AT 6:43 AM

5 Replies

Tiny
JSL MASTER TECH
  • MEMBER
  • 5 POSTS
Hello, this is Jeff. Did all the other lights come on when the Check Engine Light came on? And was that Check Engine Light flashing when it was sputtering?

This sounds like you may have more than one issue but we need to start with the misfire code that you have. Two things to start with are replacing that spark plug and checking the fuel pressure.

Here are a couple guides that will help with this:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Below is a chart that will help with identifying issues with spark plugs and the process for this cylinder 3 misfire.

However, the sputtering points more to a fuel issue only because you don't have multiple cylinders with misfires. A single cylinder will cause a vibration and slightly less power but if it has considerably less power then that sounds like a fuel issue so we need to eliminate it.

Please let me know what you find. Thanks
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Friday, June 25th, 2021 AT 7:15 AM
Tiny
JENN LYNN
  • MEMBER
  • 3 POSTS
My check engine light came on first then the other ones. Yes it flashes when sputtering. Not sure if the pictures help any.
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Friday, June 25th, 2021 AT 8:35 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
It looks like the spark plugs need replacement. I would service the MAF and throttle bore as well. Here are guides to help us get the services done:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

and

https://www.2carpros.com/articles/mass-air-flow-service

and

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

Please run down these guides and report back.
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Monday, June 28th, 2021 AT 8:43 AM
Tiny
JENN LYNN
  • MEMBER
  • 3 POSTS
So I got my spark plugs replaced all of them, my throttle serviced and my plugs or wiring whatever the ones fixed and now my car is running like a champ. I just need to figure out how to take off my service tire monitor service and also my airbag light came on when all that was coming on. So other than that that's all that I had to do for it to work. Thanks you guys.
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Saturday, July 3rd, 2021 AT 11:49 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi Jen,

What I need you to do is start a new thread related to the two additional questions. We are trying to keep the threads specific to one topic so they are more helpful to others.

I hope you understand. Here is a link for a new post. Simply copy and paste your new questions to the link and someone will be happy to help.

https://www.2carpros.com/questions/new

Thank you,

Joe
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Wednesday, July 7th, 2021 AT 9:31 PM

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