I was taking a look at a 2004 Ford Escape with 100k miles yesterday because it was infrequently stuttering, and throwing a "cylinder 5 misfiring" error code that would come on and go away.

I figured it was a good idea to change the spark plugs--since it was a relatively cheap procedure, and the owner had never done that anyway--then go from there. I was a little disappointed to find that it was more involved than the several cars I had replaced in the past. I'm by no means a mechanic, but I feel comfortable saying that I know more, and have done more, than the average person.

Anyway, as I was reluctantly deciding on how to get the intake manifold off, I noticed this:

Disconnected hose enter image description here

My buddy says it's the crankcase ventilation hose. I decided to stick it back on, get a zip tie to tighten it as best I can, and see if that helps.

I guess my question here is: Does that seem like it could be the source of the problem? And if the symptoms don't show up again, should it be reasonable to think it's fixed? (I mean, overlooking the fact that it's over 100k and could use a tune up anyway.)

1 Answer 1


Yes, the air that is passed through the crankcase ventilation system is metered before it enters the ventilation system. If the pipe is off, un-metered air will be allowed in, which will cause a weak mixture and therefore possible misfiring.

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