Miss Fire (P0304)

[sinus19]

Hey guys.

So it seems that i have a miss a fire on cylinder 4. I went ahead and changed the plug and wire along with the coil. I also swapped injectors and checked compression. Eveything turned out GOOD but the miss fire was still there. after extensive driving it turns out that it miss fires only between 3,000-4,500rpm (only while its underload) with a chatter noise coming from the valve cover. Also its starting to burn a bit of oil... I was told that the cam shaft position sensor can cause a miss fire but that dont explain the valve cover chatter... I will remove the valve cover and inspect but i wanted to hear wat you guys thought.

 

[Slitherbeast]

Remove the rocker cover. You most probably have a broken spring!

 

[VENOMOUS1 RACING]

Remove the rocker cover. You most probably have a broken spring!

Yup broke spring or collapsing lifter.

 

[sinus19]

Remove the rocker cover. You most probably have a broken spring!

Nooooo it cant possibly be my worst nightmare. Im 1,000 miles away from home! I will take of the cover this morning to confirm. If it so then im screwed big time! Ive been driving it and shifting at 2,500 rpm. Now im paranoid and freaking out on how im supposed to get back home. I will post back shortly to comfirm the broken spring.

 

[sinus19]

Popped the cover off and everything looks good! No metal shaving at all. However, I started it and i heard like a deep hissing withing the cylinder. Not sure if thats normal? (Maybe because it was a cold start?) As i had mentioned, compression test was good. I have yet to do a leakdown test.

 

[ZCx]

if it is a broke valve spring, they can fool ya/be a bit hard to see.

did ya grab a holt of each spring/valve & try up & down play???

 

[sinus19]

if it is a broke valve spring, they can fool ya/be a bit hard to see.

did ya grab a holt of each spring/valve & try up & down play???

Yes i did they were all solid.

 

[sinus19]

Would it be a valve seal?

 

[ZCx]

seal??? no noise, oil useage, yes.

might have a lifter tryin to lay down on ya.

 

[sinus19]

seal??? no noise, oil useage, yes.

might have a lifter tryin to lay down on ya.

Hmmm... well heres where gets tricky... If i down shift and EASE into the 3,000 - 4,500 range then everything sounds normal. But if i dont downsh¡ft and laydown the pedal it will miss fire bad (flashing check engine light with noise).

 

[ZCx]

sounds to me like its not mechanical.

have ya fueled up lately or been a while since ya fueled up??? might be a bad load of fuel

 

[sinus19]

sounds to me like its not mechanical.

have ya fueled up lately or been a while since ya fueled up??? might be a bad load of fuel

Checked and the plug looks clean. I will take a pic and upload it later today. Unforntunately i have to make my 1,000 mile trip back home this morning

 

[sinus19]

What The!!!
Computer kept saying P0304 and the plug on 4 was find. However i found this one on 9 just today.

 

[ZCx]

looks like oil

 

[sinus19]

looks like oil

Yes and lots of it! And the plug is only 3 weeks old. soo
Question now is.. why? Im taking it to the stealer ship to get it diagnosed tomorrow. Any ideas on what its causing it? Head gasket? Valve seal?

 

[ZCx]

stuck rings or valve seal

 

[sinus19]

Well i hope its the valve seals. Those aren't very hard to change and dont require to remove the head....right?. We'll see what the stealer ship says tomorrow. Thanks for the info ill keep ya posted!

 

[ZCx]

was she usin oil???

 

[sinus19]

Nothing noticable.

 

[10-1=9]

You most likely found her dead cylinder. Time to do a compression & leak down test.