Cap missing on vaccum line under intake manifold

[mf7365]

97 5.0 mountaineer/ Under the intake manifold on the driver side toward the firewall is a solid steel vacuum line that is capped off with a rubber cap. It is next to the pcv line running from front to back of the manifold. Somehow, the cap came off yesterday at some point while my wife was driving, and the truck was weezing and bucking, with a smattering of oil coming out of the opening on the line. I didn't even know the line was there until this happened, and the rubber cap is now missing so I had to tape it off. Anyone experience this problem, and is it just a matter of getting a new cap?

 

[99SportX]

It is very common on 97 5.0's. Just replace the cap and go on your way. You may be able to put a zip tie on the cap to hold it more securely and keep it from happening again.

 

[mf7365]

Thanks for info. Based on looking at it, it seemed like there wasn't to much keep it on once the that cap gets old, and it was in the single digits here which may have caused it to slip off too.

 

[99SportX]

Yeah, from what I have heard on these boards, the cap most commonly blows off after a failed start (not cranking long enough so the engine doesn't quite start and the engine stumbles a little and shuts down). I am not sure how it happens exactly but that is what people have said.