sanremo99

Hi guys..need your help pls. i'm having trouble with my w202 c200. Just put a new Bosch MAF to fix the cold start problem and voila It worked. But then after a while when the car is idling for 3 minutes, Cylinder 1 and 4 stops working.
I checked the Spark and its working, swap coil from 2/3 and still no response... just fitted a new spark plug same time with the Maf plus
Injector has been cleaned too. I checked the FI terminal and there is power there of 7.5 v which is normal for this engine I guess.

The following day I started the car again and goes ok first go but as soon as its start idling, cylinder 1/4 stop working. It looks like something is happening when the car goes to close loop running..I'm just wondering why its fine during warming up but cyl. 1/4 is cutting out soon as it reached the idling mode.

I compared the spark of 1/4 to 2/3 and they seem to be identical, it sort of bluish-orange..maybe not that strong but still able to ignite the fuel i guess.

Pls. help as I'm lost what to do next....Thank s guys .