Rough run. Summary


How to act if problems with NOx system are solved, the engine performs Stratified charge again, but in some conditions uneven run is noticed or 3104 error (uneven run, Stratified charge) is stored.



(1) Software upgrade of the existing release using ISTA P: The service data status ”Button designation: improve operational smoothness conversion” must be programmed via the ”conversation” path;

(2) Software upgrade using ISTA P;

(3) Software upgrade using winKFP (flashing of the correct software release, regardless of FR);

(4) Test of leaking injectors. The description here, here and here;

(5) Checking for misfire counters. Description here;

(6) Replacement of the ignition coil. Additional information here.

(7) worn spark plugs or incorrect spark plugs installed. Additional info here and here.



TOP 20+ reasons for a rough run and 3104:

  1. Most popular hidden cause: problems with NOx sensor and/or NOx catalytic converter. Detailed description here and here;
  2. Specific defect of NOx sensor – no related error messages stored. Detailed information here and here;
  3. All technical problems fixed, error messages deleted, but problem with an uneven run, fuel trim remains. Description of the situation here;
  4. MSD80 hardware problem. Snubbers of ignition coils. Description here. How to replace ignition coils – read here;
  5. 3104 error on uneven road. Investigation here. How to interpret misfire counters. Read here;
  6. incorrect spark plugs installed. Description here;
  7. 3104 error. When the algorithm fails. Description here;
  8. 3104 and proper software release. Read here, here and here;
  9. Problems with fuel adaptations. Incorrectly coded injectors. Read here;
  10. Unstable operation and rough run at idle. Problems with crankcase ventilation valve. Read here;
  11. Problems with increased emissions, increased fuel consumption – a defect of the thermostat. Read here and here (end of the article);
  12. 3104 error message without any reason. Read here (end of the article);
  13. Increased misfire counters for 1st cylinder. Data logging. Read here (end of the article);
  14. Software bugs of MSD80. TOP 10 here;
  15. N53. The problem of 3rd cylinder. Read here;
  16. Cold engine and problems of injectors. Read here.
  17. Rough run. VANOS. Read here.
  18. Problems with fuel pressure. Read here.
  19. Rough run at idle. Remaining disbalance. Read here.
  20. Problems with oil or fuel pressure, water pump, etc. Read here.
  21. Uneven run. Regeneration. Read here.


Useful links

  1. Diagnostics of MSD80. Read here.
  2. How to evaluate performance of NOx system. Description here;
  3. How to check NOx sensor. Read here;
  4. How to create flywheel adaptations. Read here;
  5. How to create N43/N53 adaptations. Read here.