yet another problem on my e240 1999

hi all

I'am slowly loosing my reason with this car but hopefully i can get it back on track. I'am currently dealing with a suspected head gasket issue but this afternoon when I tried to start the car it took a number of turns before it caught and then the idle was really bad.

I investigated the problem and found that by disconnecting either or both front coil packs it made no difference to the idle problem whereas disconnecting any of the rest makes it worse.

I then moved the cables from the front to the next coil pack and the idle was rough so i doubt that both coil packs in the front are gone as it looks like there is an issue with the supply cables going to the packs , is this possible and how can i test it to make sure all the signals/voltages are been sent ?

thanks in advance

brendan