P0304
- Thread starter Sierra946
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soundmanlpte
New member
Drivers side middle cylinder. I believe it connects to cylinder 1 which is passengers side front. Swap the coil from cylinder 1 elsewhere. I just had exact same code and it was a wire. Which I didn't discover until after I swapped fuel injectors.
Sierra946
New member
Thanks. The spark plug had actually backed itself out and was a half turn away from coming completely out. The tip of it was almost half gone. I checked the rest of the spark plugs and they were all loose. I changed them 6 months ago and they were all torqued to 13 ft/lbs. What the heck would cause that?
While driving up a very steep street my 3.4l started experiencing a rough engine feel, especially at idle. Check engine light was already on due to a P0402 code. At idle the roughness was very noticeable. When home I used the scanner to find an additional code, P0304. After some research on this sight I decided to change plugs, then wires, then coils...if necessary. First all plugs were changed. They were due. Nothing abnormal noticed and nothing changed with the code or rough idle. Then while the motor was running I pulled the wire from cylinder 2 and noticed the idle got worse. When pulling the wire from cylinder 4, no change. I then replaced the wire from cylinder 1 to 4 and idle is smooth. Codes were cleared and have not returned after a few days of driving. P0402 has not returned either.
