2009 E350 Troubleshooting - MBWorld.org Forums

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bigbluebenz

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2009 E350 Wagon, 1990 Volvo 240

2009 E350 Troubleshooting

I recently purchased a misfiring E350 wagon that I believe is cool enough to be worth saving, but I need some help narrowing down the possibilities.
When I purchased the car it had a handful of misfire codes including P0300, P0301, P0302, P0305. A PCV refresh smoothed it out, but cylinder 2 still has a consistent misfire and car continues to throw the code P0302.

First thing I did was check compression, as I knew there was decent likelihood that I had a valve issue. All six cylinders came back in the 150-160 psi range.
I also popped off the hall sensors to see if the timing looked alright, all timing marks were perfectly centered in the holes.
Next I swapped around spark plugs and coils, the misfire remained at cylinder 2.
I used a iCarsoft scan tool to watch the misfire counter and noticed that the misfires count up between 0-2000rpm and then above 2000 rpm they stop.

According to the scan tool the intake manifold pressure is reading 6.53 psi, which I'm thinking indicates a vacuum leak somewhere. I tried spraying brake cleaner around the intake, but did not notice any rpm changes. I have read that these intake manifolds have issues, but I'm not sure what the normal failure modes are. Should I try to track down a vacuum leak or just go for it and replace the whole intake manifold? I'm trying to think of a scenario where only one cylinder misfires consistently because of the manifold and I am having trouble.
Any thoughts are appreciated!