Try my way, its dead easy.... You start with a warmed up engine and then you do not start it again until it is completed.
I do mine about every 3 months to keep it spotless (DLK knows that) and all I do is to use Gunk engine cleaner from a pressure bottle, the pump up type, and if there is any heavy dirt (mine never gets the chance to get any) work it in with an old paint brush and let it stand for about 30 minutes and then give the Gunk and paintbrush another go. Let it stand 5 minutes again.
I then rinse it off over a stormdrain (it is acceptable because Gunk is biodegradable) with a standard garden hose. After that I let it stand for a bit then start it and let it run to warm up again. To finish I leather off the engine top, wing side channels and slam panel before closing the bonnet and washing the whole car before finally taking it for a run.
It has never failed to start first time and has never had any problems with misfires etc afterwards.
Yours must have had a bad owner before to have let it get so filthy, dirt can hide a multitude of sins and I would not be surprised if you now find that lots of tlc and work will be needed cos a dirty car in my view generally indicates poor service history.
Wish you gudluk though...and happy motoring...
