Hey guys I've just recently had my GTR come back from the shop, I had a new gearbox put in and the mechanic suggested some new spark plugs be put in as the others were very fouled and old, the day I brought it back I noticed a nasty misfire around 5000rpm when it starts to boost hard but would go away after being driven around for a while, but recently has gotten much worse and after I had the car sit there for a day and got washed it's now not running all cylinders and did so for a small drive, after being turned off and turned on again it ran 6 but slowly went back to running 5, I wouldn't expect any water to get on the coilpacks when I washed it as the bonnet was down, I let it sit over night and it's still running horribly. Any suggestions? I know there's plenty of things I could do but if anyone could narrow it down it would be greatly appreciated, cheers guys.