A few days ago my 2004 ralliart started making a horrible sound once the RPMs got into MIVEC range. A day later it threw a code (P0301, misfire cylinder #1) and it's still making the sound. If i keep it under 3500 RPMs i really can't notice a difference in how it drives. I uploaded a video of the sound it makes, anyone have any idea what it is? any help would be appreciated, thanks.

[youtube]XDaxUBjRTck[/youtube]

 

my guess is, due to the fact that its happening when MIVEC is supposed to kick in, its obvously something goinf wrong. im trying to read all the things the engine does different once mivec engages. expecially since it said a cyl misfired. replace your spark plugs.. also might be an air / feul mixture problem once mivec engages. have ya replaces the sparc plugs recently?

 

1. Do plugs
2. Run some Heet through your system.
3. Clean Maf

 

First off that sounds like valve floating to me. Have you done a valve adjustment? Pull that valve cover off and inspect all the rockers and springs.

What were you doing when this occurred? Meaning how were your driving the car?

More details to what you were doing when this started to occur. No worries if you driving the car like you stole it, fill in the details on this.

 

Have not done a valve adjustment. When i first noticed it i was really beating it, just a quick drive home from work and I got it up to probably 4500 in 2nd gear and noticed something sounded weird. Revved it a few times in the driveway and it hasn't stopped since. You think it's doing damage if i drive it keeping it under mivec?

 

you mean you WERENT beating it lol. and i use HEET every other fill up. you dont keep your tank full.. its gets REALLY cold over night. moisture in your gas tank... moisture in your gas lines... car trys to push alot of gas in when its hitting mivec but cant because your gas lines are clogged. ( just a thought) lol

 

Check your plugs.

A bud of mine had one busted.

 

Fouled/worn spark plugs cause misfires at higher rpm.

 

I would definitely pull the plugs and pull the valve cover and inspect everything.

 

u have drive train warranty on the car still? straight to the dealer!

 

So have you found out what is causing that valvetrain noise yet?