# 2003 Pontiac Vibe runs rough, then improves

**URL:** <https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898>\
**Category:** Maintenance/Repairs\
**Tags:** pontiac, vibe\
**Created:** [November 15, 2018, 1:40pm UTC](https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898 "2018-11-15T13:40:49Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![TimDaugherty](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@TimDaugherty](https://community.cartalk.com/u/TimDaugherty)\
**Post date:** [November 15, 2018, 1:40pm UTC](https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898/1 "2018-11-15T13:40:49Z")

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engine runs rough until 30 minutes of driving, then better. diagnostic shows cylinders 1 and 4 misfiring. Auto parts store guy suggested vacuum hose misrouted. New plugs less than a year ago.

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**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\
**Post date:** [November 15, 2018, 2:02pm UTC](https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898/2 "2018-11-15T14:02:30Z")

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> [@TimDaugherty](#):
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> diagnostic shows cylinders 1 and 4 misfiring

What exactly were the codes? Have you swapped the coils from 1 and 4 with the coils from 2 and 3? If the misfire follows the coils, replace them. If the misfire is still on 1 and 4, pull all the plugs and run a compression test. I’d guess 1 and 4 will be low. Likely very low if the engine is cold. When it warms up the rings seal a bit better and the misfire goes away.

Sooo how many miles on the engine? Lemme guess, at least 150K? Is the check engine light on all the time?

> [@TimDaugherty](#):
>
> Auto parts store guy suggested vacuum hose misrouted

Never, ever, get your diagnostic advice from the auto parts store guy.

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<div class="post-metadata">

**Author:** ![TimDaugherty](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@TimDaugherty](https://community.cartalk.com/u/TimDaugherty)\
**Post date:** [November 15, 2018, 4:28pm UTC](https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898/3 "2018-11-15T16:28:43Z")

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I swapped #4&3, and 2&1. Diagnostic was the same. Pulled the plugs. Compression test reveals #4 185, #3 175, #2 185, #1 190. Engine warm.

I am assuming #4 is on my left facing the engine

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<div class="post-metadata">

**Author:** ![TimDaugherty](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@TimDaugherty](https://community.cartalk.com/u/TimDaugherty)\
**Post date:** [November 15, 2018, 4:33pm UTC](https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898/4 "2018-11-15T16:33:37Z")

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Diagnostic codes are P0304 and P0301

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**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\
**Post date:** [November 15, 2018, 4:46pm UTC](https://community.cartalk.com/t/2003-pontiac-vibe-runs-rough-then-improves/128898/5 "2018-11-15T16:46:09Z")

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Would have been nice to know all that from the start.

How many miles on the engine?

You might try a cold compression test and swap the spark plugs as well… new or do the 1-2 and 3-4 swap.

And #4 is on your right facing the engine. #1 is on the end with the serpentine belt