[shirkenikhil@gmail.com]

I've been encountering a concerning issue with my BMW 320D GT's engine performance. When I'm not accelerating, the engine rattles heavily, but at higher RPMs, it seems to run smoothly. Additionally, I've noticed lower mileage than usual.

Upon running diagnostics, I received the following error codes:

2A6D00 Permanent Smooth running Regulator Cylinder 4: Correction Quantity outside permitted Limit
2A6D00 Permanent Smooth running Regulator Cylinder 1: Correction Quantity outside permitted Limit
Here's what I've tried so far:

Replaced fuel injector No. 4 with a new one at Cylinder 4, but the error code persists.
Replaced injector 1 with a new one, yet the error code remains.
Cleaned the EGR system, but unfortunately, the error code persists.
Ensured there are no air leaks.
Even after resetting the diagnostics tools, the error codes persist, and the engine's performance suffers when not accelerating.

I'd greatly appreciate any insights or suggestions on what could be causing these issues and how to resolve them. Any pointer to a reputable mechanic in West London will help.


Thank you in advance for your help!

[TurboWeasel]

Assuming the new injectors were coded, it could be poor compression on 1 and 4 and the ECU is trying to compensate.

Boost tends to hide cylinder contribution issues.

[Eddamoo]

"the engine rattles heavily" - Does this mean like a knocking noise?

Ive seen a few threads where, unfortunately, crankshaft bearing failure has caused these 'smooth running' codes. If you're able, pull the oil/filter and inspect for bearing material.

[shirkenikhil@gmail.com]

not knocking noise but it shakes as if its not getting sufficient fuel.
When I put my foot on the accelerator pedal engine is fine.

[shirkenikhil@gmail.com]

Originally Posted by TurboWeasel

Assuming the new injectors were coded, it could be poor compression on 1 and 4 and the ECU is trying to compensate.

Boost tends to hide cylinder contribution issues.

Can you advise what can be done to fix the compression issue ?

[TurboWeasel]

I would take it in to expert for diagnosis before going down that road. If the rattling goes with revs, it might be slack chains.