Vacuum Leak 2.5L Engine

[sric]

Hello Everyone,

I am new to this forum, so a quick intro is in order. I own a 2001 Subaru Outback wagon with a 4-cyl. 2.5L engine. I am the second owner. The car has approximately 222K miles on the odometer.

Recently, the check engine light came on with a P0304 code. Misfire in cylinder 4. I did the obvious: Replaced the spark plug in that cylinder and checked the coil pack and spark plug wire. Both good. Convinced that I might have a tight valve in that cylinder, I took it to my mechanic for a compression check. The compression is good.

Bottom line: He did the smoke and spray test and discovered a vacuum leak in one of the hoses. He replaced the hose, but there is another leak under the intake manifold. The source of the leak is not visible. Before we remove the intake manifold to investigate further, has anyone out there encountered this problem? And, if so, is there some way around this, other than having to remove the intake manifold for further observation?

Thanks in advance for your help.

 

[Ecmbuster]

There is no way around that problem. A "smoke test" will help to identify the cause of the leak.
Check all hoses and clamps, EGR for leakage or sticking and replace the PCV.

 

[sric]

Thanks. We have done a smoke test and identified a hose that had a split, which we replaced. Not the main culprit, however.
That villain is hiding under the intake manifold and hidden from view.