# Engine Idles erratically

**URL:** <https://community.cartalk.com/t/engine-idles-erratically/6151>\
**Category:** Maintenance/Repairs\
**Created:** [October 18, 2007, 10:13pm UTC](https://community.cartalk.com/t/engine-idles-erratically/6151 "2007-10-18T22:13:07Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![JamesBryant](https://avatars.discourse-cdn.com/v4/letter/j/e36b37/32.png) [@JamesBryant](https://community.cartalk.com/u/JamesBryant)\
**Post date:** [October 18, 2007, 10:13pm UTC](https://community.cartalk.com/t/engine-idles-erratically/6151/1 "2007-10-18T22:13:07Z")

</div>

I have 1991 ford F-150 that idles erratically up and could idles Down and have install a speed control motor and has worked. HELP!!

---

<div class="post-metadata">

**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\
**Post date:** [October 19, 2007, 1:37am UTC](https://community.cartalk.com/t/engine-idles-erratically/6151/2 "2007-10-19T01:37:25Z")

</div>

Look for vacuum leaks. They cause the same symptoms.

---

<div class="post-metadata">

**Author:** ![Roadrunner](https://avatars.discourse-cdn.com/v4/letter/r/d2c977/32.png) [@Roadrunner](https://community.cartalk.com/u/Roadrunner)\
**Post date:** [October 19, 2007, 2:50am UTC](https://community.cartalk.com/t/engine-idles-erratically/6151/3 "2007-10-19T02:50:08Z")

</div>

You may have a faulty IAC valve and/or a dirty throttle body.