# Rough idle, what is this pvc tube called?

**URL:** <https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788>\
**Category:** Maintenance/Repairs\
**Created:** [August 2, 2019, 7:22am UTC](https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788 "2019-08-02T07:22:26Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![John-Smith-4](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@John-Smith-4](https://community.cartalk.com/u/John-Smith-4)\
**Post date:** [August 2, 2019, 7:22am UTC](https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788/1 "2019-08-02T07:22:27Z")

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So my car check engine light has been on for a while, but it runs smoothly. This morning it was cold as, and the car started up roughly. Jolting etc, but only on idle. When I accelerated it ran smooth.

I took out all the ignition coils and checked each one, they look fine. The spark plugs are only 6 months old. But I noticed this pvc tube that had a shoddy repair done to it. It looked like it cracked and someone glued it, and now it has cracked again.

Any idea what the tube is called exactly? So I can order a replacement. [http://imgur.com/a/HbUJ2bJ](http://imgur.com/a/HbUJ2bJ)

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**Author:** ![It\_s-Me](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/it_s-me/32/12660_2.png) [@It\_s-Me](https://community.cartalk.com/u/It_s-Me)\
**Post date:** [August 2, 2019, 12:42pm UTC](https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788/2 "2019-08-02T12:42:14Z")

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Near as I can tell, That tube looks OK, it’s the busted up PCV valve that looks bad.

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**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\
**Post date:** [August 2, 2019, 5:11pm UTC](https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788/3 "2019-08-02T17:11:08Z")

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Have you bothered to get the codes read? Most autoparts stores will do that for free. Be sure to record the code, it will be a P followed by 4 numbers, i.e. P0300. Report that code here nad you will get a lot more help.

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**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\
**Post date:** [August 2, 2019, 5:53pm UTC](https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788/4 "2019-08-02T17:53:39Z")

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That is the “breather” tube or “make-up air” tube, it is part of the positive crankcase ventilation system.

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**Author:** ![John-Smith-4](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@John-Smith-4](https://community.cartalk.com/u/John-Smith-4)\
**Post date:** [August 4, 2019, 1:19am UTC](https://community.cartalk.com/t/rough-idle-what-is-this-pvc-tube-called/145788/5 "2019-08-04T01:19:09Z")

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![20190804_111548](https://global.discourse-cdn.com/cartalk/original/3X/6/d/6dc3281dc7ca1b745267bab37c1ae77deb4e5e18.jpeg)

P2178, P2189 with P0300 would lean towards a vacuum leak?

The battery is pretty new and good quality, can’t see how the voltage would be too low unless something is draining it (the AC?)