Trying to track down the cause of misfire codes on an FSI - problem arose on starting, the car had been parked for a couple of hours after a brisk 40 mile motorway journey. Engine light was flashing at idle and the following codes weres stored:
16684 - Random/Multiple Cylinder Misfire Detected;
16685 - Cylinder 1: Misfire Detected; and
16687 - Cylinder 3: Misfire Detected.
The flashing check engine light goes out when driving and returns when sitting at idle - there is a very slight but noticeable roughness to the idle, just evident in the rev counter needle. Occasionally it will illuminate constantly, but only briefly.
Plugs are about 5k miles old and are all in good condition and the same good colour; I've swapped all plugs and coilpacks, but the fault codes stay with cylinders 1 and 3.
The only problem I've found is a tiny pinhole in the corrugated EGR pipe, which looks like it has been caused by the wiring bracket attached to the side of the head rubbing on it - I covered this with a blob of superglue as a temporary test, but it hasn't made any difference.
I've also cleaned the main earth on the chassis rail and the one on the cylinder head (both were already clean and didn't really need doing) and gone through all the visible ignition connectors with contact cleaner. I also reset the throttle body with VCDS, just to see if it made any difference (it didn't); inlet and throttle body both look very clean. It's had two or three cans of Normfest fuel system cleaner through it over the past year and the fuel filter is also about 5k miles old. It has always been run on Super Unleaded in my ownership (V-Power whererever possible) and has done about 104k.
Any other suggestions before a compression test and pulling the injectors?
16684 - Random/Multiple Cylinder Misfire Detected;
16685 - Cylinder 1: Misfire Detected; and
16687 - Cylinder 3: Misfire Detected.
The flashing check engine light goes out when driving and returns when sitting at idle - there is a very slight but noticeable roughness to the idle, just evident in the rev counter needle. Occasionally it will illuminate constantly, but only briefly.
Plugs are about 5k miles old and are all in good condition and the same good colour; I've swapped all plugs and coilpacks, but the fault codes stay with cylinders 1 and 3.
The only problem I've found is a tiny pinhole in the corrugated EGR pipe, which looks like it has been caused by the wiring bracket attached to the side of the head rubbing on it - I covered this with a blob of superglue as a temporary test, but it hasn't made any difference.
I've also cleaned the main earth on the chassis rail and the one on the cylinder head (both were already clean and didn't really need doing) and gone through all the visible ignition connectors with contact cleaner. I also reset the throttle body with VCDS, just to see if it made any difference (it didn't); inlet and throttle body both look very clean. It's had two or three cans of Normfest fuel system cleaner through it over the past year and the fuel filter is also about 5k miles old. It has always been run on Super Unleaded in my ownership (V-Power whererever possible) and has done about 104k.
Any other suggestions before a compression test and pulling the injectors?