P0304

[george1904]

so im getting a P0304 code which is a 3 cylinder misfire. I changed my spark plugs and got new wires but the it is still throwing the same code. what else can i do to fix it?

 

[tjbiker031]

could be a bad coil.

 

[PieEyedPiper]

so im getting a P0304 code which is a 3 cylinder misfire. I changed my spark plugs and got new wires but the it is still throwing the same code. what else can i do to fix it?

Unless I'm mistaken P0304 is a Cylinder 4 misfire. Check for oil in the plug wells, you could need a new VC gasket. I would also check the coils, like mentioned above.

But first check the basics, can you please answer all these for us?
What brand and model plugs are you using?
What measurement did you gap the plugs to?

 

[rush2252]

this is on the GST correct? just wandering. Also it could be a dead injector. You can take a long screwdriver and use it as a tuning pitch. Stick the end on the injector while the cars idling and stick your ear upto the handle you should hear a sharp clicking if its working. Check the sound of all 4 make sure you place the screwdriver in the same position as not to distort readings! this also works for checking wheel bearings etc if theres no play but you know they might be bad

 

[george1904]

Unless I'm mistaken P0304 is a Cylinder 4 misfire. Check for oil in the plug wells, you could need a new VC gasket. I would also check the coils, like mentioned above.

But first check the basics, can you please answer all these for us?
What brand and model plugs are you using?
What measurement did you gap the plugs to?

my bad it is cylinder 4.I checked the coil and they seem fine and I have Bosch plugs and the spark plugs are gapped .32

 

[george1904]

this is on the GST correct? just wandering. Also it could be a dead injector. You can take a long screwdriver and use it as a tuning pitch. Stick the end on the injector while the cars idling and stick your ear upto the handle you should hear a sharp clicking if its working. Check the sound of all 4 make sure you place the screwdriver in the same position as not to distort readings! this also works for checking wheel bearings etc if theres no play but you know they might be bad

i checked and they seem to be working. I even put some other injectors and still the same

 

[nightracer91]

I'm not a huge fan of bosch plugs at all. I see nothing but problems out of them. Have you used a spark tester to make sure there truely is spark at the plug? You said you swapped injectors already? Are those injectors flowing properly? I had one injector that must have had some crap in it because instead of spraying a mist, it sprayed in two streams causing a misfire. Did you try moving the injector from 4 to another cylinder to see if the misfire followed? There are four things that you need for a power stroke: spark, fuel, air, and compression. If you do have spark and fuel, then the problem might be in the other two.

 

[george1904]

I'm not a huge fan of bosch plugs at all. I see nothing but problems out of them. Have you used a spark tester to make sure there truely is spark at the plug? You said you swapped injectors already? Are those injectors flowing properly? I had one injector that must have had some crap in it because instead of spraying a mist, it sprayed in two streams causing a misfire. Did you try moving the injector from 4 to another cylinder to see if the misfire followed? There are four things that you need for a power stroke: spark, fuel, air, and compression. If you do have spark and fuel, then the problem might be in the other two.

I'll go swap them and I'll post the results

 

[kenamond]

NGK BPR6ES plugs gapped to 0.028". $2/each at NAPA.

Check compression.

I've never had to muck with my ignition system, but as I recall, one coil drives 1 & 4, so if that coil is bad, you'd misfire on #1, too, right?

If you haven't already, check for oil in the plug wells as was recommended. It can cause arcing within the plug wire boot and misfire.

 

[george1904]

NGK BPR6ES plugs gapped to 0.028". $2/each at NAPA.

yea i was actually going to go get some tomorrow
hopefully this fix the problem thanks

 

[kenamond]

yea i was actually going to go get some tomorrow
hopefully this fix the problem thanks

I added some more info to my post.

 

[kp116]

How did you "check" the coil? Looking at it really doesn't do anything.... Have you tried a known good power transistor?