Citroen C4 Uneven Idle and Error

Sounds like you're on the right track. Defective engine mounts are common with those symptoms. Have you inspected the transmission mount? Sometimes a failed transmission mount can mimic engine mount problems. What diagnostic trouble codes are you seeing?

Thanks! I haven't checked the transmission mount, but I will. Where should I look for problems on the transmission mount? The error code is P0299, pointing to a turbo underboost condition, but the rough idling made me think engine mount.

P0299 could be misleading. While a turbo issue is possible, the engine mount might be the root cause, creating vibrations affecting sensor readings. Given the symptoms and error code, I'd suggest a trusted workshop for a proper diagnosis. They can pinpoint the exact cause and save you time and potential damage.

Okay, I appreciate the advice. I took it to a local shop, and you were right. A faulty engine mount connection was throwing off readings and causing the uneven idle. They replaced the mount and fixed the connection for 95€. Runs like a charm now. Thanks again!