P0304, #4cyl low compression

123klee
Posts: 1
Joined: Thu Mar 14, 2013 11:40 am

P0304, #4cyl low compression

Unread post by 123klee » Thu Mar 14, 2013 11:46 am

2002 Montana 3.4
It started a week ago I was Idleing at a coffee shop when it started running rough. Checked spark-good,chkd fuel - good, compression in #4 is 30 lbs. I am not having any coolant issues ie;leaking or mixing with oil, blows good heat. I had a head gasket job done a year ago.

Please help disabled man needs his van back

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Karl
Posts: 83
Joined: Thu Oct 11, 2012 3:43 pm

Re: P0304, #4cyl low compression

Unread post by Karl » Fri Mar 15, 2013 2:29 pm

This may be the common problem, especially after intake gaskets replaced. A rocker arm bolt may have pulled the treads out of the head and now the rocker is not fiunctioning. This will cause a misfire, can cause low compression or even engine noise.

You will need to remove the valve cover to check for that. If this is the case, it may have also bent a pushrod.

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