# Engine performance

**URL:** <https://community.cartalk.com/t/engine-performance/15725>\
**Category:** Power/Fuel\
**Tags:** gasoline\
**Created:** [June 23, 2008, 12:13pm UTC](https://community.cartalk.com/t/engine-performance/15725 "2008-06-23T12:13:21Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bremoh](https://avatars.discourse-cdn.com/v4/letter/b/eb8c5e/32.png) [@bremoh](https://community.cartalk.com/u/bremoh)\
**Post date:** [June 23, 2008, 12:13pm UTC](https://community.cartalk.com/t/engine-performance/15725/1 "2008-06-23T12:13:21Z")

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Does a gasoline engine consume more gasoline when a car is coasting downhill in gear or out of gear.

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**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\
**Post date:** [June 23, 2008, 1:57pm UTC](https://community.cartalk.com/t/engine-performance/15725/2 "2008-06-23T13:57:27Z")

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with manual transmission:  
It uses more gasoline to keep the engine running at idle, out of gear. When in gear, the drive train drives the engine, and the fuel is cut off (injectors).

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**Author:** ![RogerB34](https://avatars.discourse-cdn.com/v4/letter/r/db5fbb/32.png) [@RogerB34](https://community.cartalk.com/u/RogerB34)\
**Post date:** [June 24, 2008, 6:49pm UTC](https://community.cartalk.com/t/engine-performance/15725/3 "2008-06-24T18:49:09Z")

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Fuel is also cut off automatic transmission when decel above about 1500 rpm.  
On long downhill at idle, fuel injectors are periodically activated by PCM to maintain cat temp.

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**Author:** ![bremoh](https://avatars.discourse-cdn.com/v4/letter/b/eb8c5e/32.png) [@bremoh](https://community.cartalk.com/u/bremoh)\
**Post date:** [June 25, 2008, 12:14pm UTC](https://community.cartalk.com/t/engine-performance/15725/4 "2008-06-25T12:14:23Z")

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Great information. Thanks for the help.