Astra J 2011 1.7Cdti Juddering in higher gears

[Mark72]

Hi all,

After a previous post about intermittent lack of power, and having replaced the EGR valve with a brand new one, another fault or previous one now getting worse.
In gears 4-6 if the revs are below 1500 rpm there is a pronounced juddering from the engine at any throttle input until about 1800 rpm but it’s more pronounced in 5th and 6th. I’ve physically checked the turbo and it’s free with no excess play, the vacuum pipes are all whole as far as I can tell, the swirl flap actuator is free and I have seen it moving but only when shutting the engine down. No fault codes found using code reader. I’ve a feeling it could be a vacuum operated type fault controlling turbo boost. Looking for some help from anyone who has experienced this type of fault previously.

Any help greatly appreciated.

Ps don’t have any diagnostic gear other than a basic engine code reader any recommendations for an adequate piece of kit would be helpful.

Cheers

Mark


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