# P0304 intermittent misfire only in first... on accel

**URL:** <https://community.cartalk.com/t/p0304-intermittent-misfire-only-in-first-on-accel/113943>\
**Category:** Maintenance/Repairs\
**Tags:** kia, rio\
**Created:** [March 18, 2018, 8:22pm UTC](https://community.cartalk.com/t/p0304-intermittent-misfire-only-in-first-on-accel/113943 "2018-03-18T20:22:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![geo\_mac](https://avatars.discourse-cdn.com/v4/letter/g/9fc29f/32.png) [@geo\_mac](https://community.cartalk.com/u/geo_mac)\
**Post date:** [March 18, 2018, 8:22pm UTC](https://community.cartalk.com/t/p0304-intermittent-misfire-only-in-first-on-accel/113943/1 "2018-03-18T20:22:47Z")

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Hello and thanks … 2005 Rio with 130 000 - 5 speed … burning a bit of oil but otherwise runs ok.

Car runs and drives without problems, but once in a while, several times a week, it will miss fire on take off. Starting out in first, it will hesitate, lose power; I feather the gas, the RPM’s come back and car runs normal . However, If I go WOT , the car will set a soft 304, it will continue to run rough, until I restart the car, the MIL is off and car is ok.

I have done a tune up, plugs wires, coil, and replaced wires connecting to the coil. Any thought would be helpful thank you  
Geo

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**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\
**Post date:** [March 19, 2018, 1:52pm UTC](https://community.cartalk.com/t/p0304-intermittent-misfire-only-in-first-on-accel/113943/2 "2018-03-19T13:52:41Z")

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Check valve clearance. Do a compression test.

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**Author:** ![Johnnybjohnny](https://avatars.discourse-cdn.com/v4/letter/j/8e8cbc/32.png) [@Johnnybjohnny](https://community.cartalk.com/u/Johnnybjohnny)\
**Post date:** [March 19, 2018, 7:07pm UTC](https://community.cartalk.com/t/p0304-intermittent-misfire-only-in-first-on-accel/113943/3 "2018-03-19T19:07:17Z")

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Replace the knock sensor. I also have a Kia Rio and had the same problem. Replaced the sensor, cleared the code a walaa it runs great again. As for the smoking when you first start it, mine too, it’s the valve guides. I go through about a quart of oil in my 3500 miles between oil changes.