I have noticed that the diesel car idles high (1400-1600 RMP) in Idle. This is occasional and some times the engine check light comes on and goes off. scanned the system, but was not able to find any errors.
during the high idle, the engine sounds rough, and while accelerating, the performance is higher without any turbo lag but with huge amount of smoke.
does any one knows what the issue is and is there any proper cause for this issue?