Code P0303, misfire?

Tiny
DJMEATMAN
  • MEMBER
  • 2010 JEEP WRANGLER
  • 3.8L
  • V6
  • 4WD
  • AUTOMATIC
  • 275,000 MILES
Got a P0303 code, so far, I have changed the coil, plugs, plug wires. Ran fine after sat for a day started up and threw the P0303 code again. What should my next project be injector maybe?
Monday, May 22nd, 2023 AT 11:28 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,256 POSTS
Yep, the fuel injector would be next. Can I ask if the engine is making a slight ticking sound? If so, can you please shoot a quick video with your phone so I can hear the noise? that way I can tell for sure what's going on. You can upload it here with your response. You might have a valve train problem.

Here is how to change the fuel injector out and a guide on misfire problems:

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

and

https://www.2carpros.com/articles/symptoms-of-engine-misfires-a-step-by-step-guide

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
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Monday, May 22nd, 2023 AT 5:58 PM
Tiny
DJMEATMAN
  • MEMBER
  • 2 POSTS
Okay, thank you. No ticking, so my next project will be injectors, should I replace all 6 while I have it apart being it has 275,000 miles and I don't know if they are the original ones?
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Tuesday, May 23rd, 2023 AT 10:10 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,256 POSTS
Yep, that would be the next step. Also, I have seen these engines have a lot of intake port carbon build up which can cause misfire issues. Have you done a compression test?

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.
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Thursday, May 25th, 2023 AT 9:36 AM

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