Misfire and hunting with codes p0300, p0301, p0302, p0303 and p0304

2007 VAUXHALL ZAFIRA
103,000 MILES • 1.6L • 4 CYL • MANUAL
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AARON1991
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The car is hunting and shaking taking time to build up speed. I have fit new coil pack, new spark plugs today. I fitted new coolant sensor and new o2 sensor still the same. could you tell me why is bringing up p0300, p0301, p0302, p0303 and p0304 please?
Mar 18, 2021 at 2:34 PM
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KASEKENNY
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The codes are telling you that you have misfires on all the cylinders. So we need to start with the basics and make sure we don't have vacuum leaks, we have proper fuel pressure, and the compression is okay. Here are guides that will help with each of these:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let's run through all of this but I suspect you have an issue with the head being warped. has the engine overheated recently?
Mar 19, 2021 at 5:51 PM