How do I check for a vacuum leak on a 2004 3.7 liberty, code says it could be a vacuum leak for rich bank 2

Asked by Dec 01, 2016 at 02:03 PM about the 2004 Jeep Liberty

Question type: Maintenance & Repair

I have a 2004 3.7liberty. I keep getting a rich bank code and only one plug is
fouling. Code says it could be a vacuum leak on the intake manifold, how to I
see where the vacuum leak could be?

3 Answers


A Vacuum leak should make it run lean, not rich. If you look for loose or cracked vacuum hoses you might find a leak but I don't think that is your problem. I would suspect a leaking fuel injector in the cylinder with the fouled plug.

Ive changed out the injector and spark plugs.

Turned out it was a dropped valve seat. I did a compression test and that was how I figured it out. Just a heads up to anyone else with the same issue.

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