Hiya, I am new here and am hoping someone can give me a little help please. I did some searches in the forum, but just kept getting "no matches found".

I have an M3 (2007) and have had a little engine flutter for a few months under load, which has got worse until now the engine fault light has come on. I plugged in an OBD reader and got code PO307, cylinder 7 misfire. It has been getting worse, but when cruising all is fine. Only when I give it some welly then I can feel the flutter to the point today that it put the car into a limp mode. On switching off the ignition and back on, the limp mode was deactivated.

So I need to check out the coil packs, switch them around etc to establish whether it is that causing the misfire. Does any know of any online guides / video tutorials for doing this on the M3 V8? For example, I need to know, which cylinder is number 7 and whether the coil packs are as easy to change as those found on earlier smaller engine BMW's which I have found tutorials for on Youtube?

I just prefer to have a good read and gather up as much information as possible before going in head first and having a route around.

Thanks in advance.