Code PO304

MAMADETTE4

MEMBER
2007 SATURN VUE
3.5L
V6
2WD
AUTOMATIC
198,000 MILES

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.

Wednesday, November 3rd, 2021 AT 10:10 PM

1 Reply

ASEMASTER6371

MECHANIC
52,797 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