Hello, for a few weeks now my Colt Z30 (BJ2005, 1.3l, 70kW) automatic has been jerking especially in certain speed ranges such as 1700-2200 RPM and with constant gas in this mentioned speed range. You can also notice it when accelerating but most clearly if you hold the speed up to 60 km/h. I had already suspected that it might be the spark plugs, so I made them out and saw that the candle shaft on the cylinder 1 is rusty and the ignition coil on the housing also has rust approaches, can it possibly be because of it? Spark plugs have now about 15-20000 km on it. Vehicle is driven little about 9000 km a year and rather short distance. Error memory read out with a launch tester, no entries available. I read in the net that it often occurs at the Colt that the throttle flap can be dirty. I bought the car since 2005 there again. For tips I am very grateful to you.