Ok then .. long post i feel ..
Fault codes
P0300 / general misfire seen
P0301 / Misfire on cyl 1
P0305 / Misfire on cyl 5
P0264 / Fuel injector cyl 2 below limit
p0261 / Fuel injector cyl 1 below limit
p0273 / Fuel injector cyl 5 below limit
p0037 / Ho2s heater circuit low .. no voltage i expect.
p0270 / Fuel injector cyl 4 below limit
p0267 / Fuel injector cyl 3 below limit
p0057 / Ho2s heater circuit low .. again no voltage i expect .
The only fuel injector not listed is no. 6 !
Basically these will all be consistent with the fuse C2 blowing other than the first 2 .. misfires .. strange we didnt get more misfires but i'm guessing there was a limit to what the dme could see as it died .
What could cause it though ...
well we have a fuse that keeps blowing that powers the coils , the injectors and the heater circuit of the lambda sensors .
Any one of these could have an internal short circuit to earth and cause it as could the feed wire to anyone of these be shorted out .
A visual check of each is needed and possibly unplugging every item .. at that point it's pining out all the wiring for the power side to each item for a short .. you would have to unplug Every item to do this test or you will just get a back feed via one of the other items .
relay pos 2 term 87 to each component .
I have a slight hunch .. or at least somewhere for you to start ..
It's a Targa .. let's say i know them rather well .. they leak and one main place they leak is at the rear drains .. this works its way forward soaking the carpet as it goes ..
The Dme and indeed the relay support is in the line of fire here .. fold down the rear seats ..
Pull out the carpet behind them .. pull in the center and up .. it pushes under the side quarter panels ..
Undo the x5 10 mm nuts and pull up the ally panels .
You know have access to the dme and the relay panel .. any water damage ?
The relay that powers everything is pos 2 in that board .. if you pull that , replace the fuse then you can see if it blows .. if not then we are onto some item or wiring engine bay side shorting out as first mentioned above .
also .. unrelated to a degree but look under the passenger seat .. alarm control unit is there .. make sure it's all nice and dry .
What info do you have to fault find .. diagrams etc ?
Pm me what you might need and ill see if i can find anything .
Time for a beer methinks .. fingers hurt after this post