when you say fuel prob by the sound of it if your pulling the ht lead and the revs drop and the same for the injector plug its getting spark and fuel but thats only a vauge test by now you should have changed the ht lead and the plug the ecu checked out good the coil packs been changed the new plug is wet but with what comp test is same on all four that eliminates the valves anything major with the head you havent said owt about a sniff test or pressure tested the cooling system to se if owt is getting past the head gasket i now you said it the dogs nads one but it might be the fault of the head it self not the h/g you have to try this as a proses of elimination comp test dont allways check out do this but get it warm even if it runs like shit get the stat open when the motor is hot you might have a hairline crack opening up when cold it might close make sure its not oil over the plug is the plug unusually clean when you take it out is it getting a bit of a steam clean in there after all that and not intill i would then focus on the fuel injection side i dont no fuk all about that side i no peeps have said the metering unit/devise can cause similer probs you its not loosing water but it only got be a tiny amount