In two years the engine light popup only 2 times..but meanwhile the car feels a bit sluggish, sometimes stall at low speed, vibrates/shudder when pulling or when starts moving, changed spark plugs and cleaned EGR (2 weeks ago), it improved a little bit, but not much. It has manual transmission.
I suppose the spark plugs are OK.
Changing the ignition coils from one cylinder to another, may take quite a long time to fire a error code, so i´m willing to change 4 ignition coils..