# Car Trouble.  Please help.

**URL:** <https://boards.straightdope.com/t/car-trouble-please-help/88222>\
**Category:** Factual Questions\
**Created:** [October 18, 2001, 3:23pm UTC](https://boards.straightdope.com/t/car-trouble-please-help/88222 "2001-10-18T15:23:58Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![RufusLeaking](https://avatars.discourse-cdn.com/v4/letter/r/c5a1d2/32.png) [@RufusLeaking](https://boards.straightdope.com/u/RufusLeaking)\
**Post date:** [October 18, 2001, 7:09pm UTC](https://boards.straightdope.com/t/car-trouble-please-help/88222/3 "2001-10-18T19:09:17Z")

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Might also be a vacuum leak in the intake manifold that only opens up when the engine is warm.

I’ve been told that this can be checked by venting a small amount of propane around suspicious portion of intake manifold while engine is running – engine will speed up if there is a leak. I’ve never done this myself and it sounds dangerous. Can a mechanic comment on this technique?

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