check engine again

[mlbenz00]

hey, here is what happened, my girlfriend was driving the 2000 ml320 one night, well acctually she started the car and drove off while the engine was cold and the check engine light came on, so i took it to the benz dealership. They said two coils are bad and wanted $550 for labor and parts. It have never seen two coils going bad at the same time so i got the scan tool from work and turned the check engine light off and the car was driving fine. I knew it wasn't the coils. The car ran fine for about 10 days and today the saem thing happend, check engine light came on again but the car is still running fine, i did not turn it off yet. If anyone has any idea what is going on, please reply i know that the coils are fine. I believe i heard one time that if it is cold outside and moist thatit could happen that the coil want fire but evetually gets hot and fires. thanks

[Q]

Have you replaced your plug wires yet? Mine failed at 55k miles and took a coil with it. You can test them quite easily. They should be 2.2k ohms. I believe the value is stamped on the boot. You can buy them individually too.

[mlbenz00]

see, thats what i was thinking too, both times the scaner showed me number 4 and 5 cylinder missfire but it also had a code with random mulitiple missfire. I guess i am going to try the 4 and 5 wires first and you said they should have 2.2 ohm reading? thanks
Also will the benz dealer sell the wires by piece or do i have to get it somewhere else?

[Q]

2.2 kilo-ohms. It's stamped on the boot.