I will chip in to say my car is behaving exactly the same as others in this thread. It started 2 weeks ago. Rough idle, car shaking, popping through the exhaust and the same pulsing sound near the drivers headlight as posted in the video a page or 2 back. Also the emissions light coming on when i bought it on the drive home early December. The o2 sensor was replaced. Emissions light stayed off after that. (Well it didn't but i'll get to that.)
Combined with this i noticed quite poor mpg. Then 3 days after these symptoms the car broke down. Basically on the way to work on xmas eve the car lost all power and wanted to stall. Misfiring like mad and the emissions light came on and was constantly flashing. I managed to get in a car park and it stalled. And would not restart. AA took it back to where i bought it (a mazda dealer) and i only got it back today.
This is what they said
Check for running fault, engine light on (It was the emissions light), missfire on no2 cyl recorded. Replaced HT leads fault still there. Removed spark plugs and carry out compression check. No 2 cyl intermittant. Remove Cylinder head and dismantle for inspection. No2 inlet valve spring broken. Remove all valves and springs. Re-grind all valves and reassemble cylinder head. Refit and test. All ok
All is well now except the same symptons as the video posted earlier. So these symptoms must be the timing now. As the work done above didn't fix any of rough idle ect problems. I thought all the the problems my car had were related. The rough idle, emissions light and the breaking down. But it appears not.
My belts were changed in dec 2010 @ 76k miles by Renault. They also changed the waterpump then but not the dephasor. Well i guess they didn't as it's not on the reciept. Car is now on 92k miles. So it looks like they didn't do a great job (not suprising after reading this site so much lately) and now they need doing again