# Why does it do this? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** eclipse, mitsubishi\ **Created:** [May 19, 2010, 7:45pm UTC](https://community.cartalk.com/t/why-does-it-do-this/49076 "2010-05-19T19:45:44Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![dtracy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dtracy/32/933_2.png) [@dtracy](https://community.cartalk.com/u/dtracy)\ **Post date:** [May 19, 2010, 7:45pm UTC](https://community.cartalk.com/t/why-does-it-do-this/49076/1 "2010-05-19T19:45:44Z")
98 Mitsubishi Eclipse, 2.0L non-turbo, 5-speed. Background: The car is parked on a slight incline facing downhill. Every morning when I start it, it idles at 1000 rpm standing still. It’s in neutral and I let off the parking brake and let it coast very slowly (1/2 mph) and it stays at 1000 rpm. If I let it coast up to 3 mph (still in neutral) it will suddenly speed up to 2000 rpm and stay there until I put it in gear to start driving off. Why is this? Is there something in the computer that detects the speed and speeds the engine up? ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [May 19, 2010, 7:58pm UTC](https://community.cartalk.com/t/why-does-it-do-this/49076/2 "2010-05-19T19:58:01Z")
" Is there something in the computer that detects the speed and speeds the engine up?" Yes. (I assume you have a manual transmission.) ---
**Author:** ![dtracy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/dtracy/32/933_2.png) [@dtracy](https://community.cartalk.com/u/dtracy)\ **Post date:** [May 19, 2010, 8:31pm UTC](https://community.cartalk.com/t/why-does-it-do-this/49076/3 "2010-05-19T20:31:53Z")
yes, it’s a 5-speed…and it does this without pushing in on the clutch or putting it in gear. I can creep down the driveway and it will stay at 1000. If I let it speed up past a couple mph, it goes to 2000 rpm. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [May 19, 2010, 8:36pm UTC](https://community.cartalk.com/t/why-does-it-do-this/49076/4 "2010-05-19T20:36:10Z")
There is a speed sensor on the output shaft of your transmission. You computer is aware the car is moving and it must get a little confused… ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [May 19, 2010, 9:00pm UTC](https://community.cartalk.com/t/why-does-it-do-this/49076/5 "2010-05-19T21:00:18Z")
I doubt that it is confused. It is getting ready for the OP to put the car in gear.