Because I don't plan to do it here, the plan is to give it to a shop. The EFI kit is a little expensive, but so are all the parts I need to change related to the K-jet. So if I can quick fix it, its better, will have a closer look tomorrow. But no I am not sure it's the wiring, the idle control computer has been replaced by the previous owner though, and he made home made connectors and wire going to components from that unit. The home made wires got a bunch of cracks, especially the wire going to the temp sensor. The unit in mine is from 87 500SEL, mine is a 88 560, and from what I understand, i need a us spec 560 controll unit for it to function properly, but don't know if that my case, since the wires don't have any power. The green stuff on the control board itself, did have a few minor scratches, and plugging it in, made little to no difference on the idle.