My Punto E+ (FIRE 1.4 engine) has run close to 55000 kms so far without any problem. Today after a short trip I got down from the car to open the gate. I noticed engine idling sound has changed. I heard engine sound is modulated up-down-up-down. To give you an idea it is like the rrrr ... rrrrr ... rrrr modulated idling sound of old KSRTC buses. Engine is not stalling or showing any other problem. Mileage is as usual. No smoke. No other problem at this time (touch wood). Switching off the engine and starting it after some time makes it ok. Any idea what may be causing this? --- Double Post Merged, Jan 16, 2016, Original Post Date: Jan 16, 2016 --- By the sound it feels like engine RPM is going up and down but the RPM needle remains stable at whatever is the normal idle speed (800 rpm?).