Code Po304

2007 SATURN VUE
198,000 MILES • 3.5L • V6 • 2WD • AUTOMATIC
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MAMADETTE4
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  • 1 POST
Replaced coil on cylinder 4. put new spark plugs in it. then we were getting the misfire for cylinder 1, 2, and 4. drove it a little more than only got the misfire on cylinder 4. What could be causing this? It is driving my other half crazy.
Nov 3, 2021 at 10:10 PM
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ASEMASTER6371
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  • 52,796 POSTS
Good morning,

The first thing I would do is check the compression to be sure the engine is good.

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

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

Then I would test the fuel pressure. You need to be sure sufficient fuel is getting to the cylinders.

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

Fuel Pressure (Key ON, Engine OFF) .................... 330-382 kPa (48-56 psi)

Roy
Nov 4, 2021 at 2:35 AM