Motor Problems.

[Spaz]

Hey guys, I don't know much about mechanics so I have no clue on what is going on with my car so I thought i'd ask on here.

My car has been sitting for a month or two now as I had some engine problems, it is about time I got around to working out what the problem is so i can fix it.

I have a D15B7, when I got the car about 4 months ago it was running fine and all seemed perfect. About a month after purchasing it started losing revs on idle, it wouldn't do this all the time maybe once or twice a week. I took it for a drive one night and it was losing revs again, i drive for about 10 minutes and pulled over at a petrol station and I could hear steam coming around from somewhere under the fuel rail not exactly sure where. Anyway after I started it back up it started chugging along sounding like a tractor so I took it straight home.
The next day I drove it around the corner and it was running fine no weird sounds or anything I stopped at a mates place and it was fine, when I was going to leave I started the car and it didnt want to start. I checked fluids and it seemed to have no coolent so i filled it up with water and go to start it again and nothing still didnt want to start, check coolant again and there is nothing there, there are no leaks under the car at all so I am unsure where it is going, oil isnt cloudy or anything like that.
Anyway I can't really afford to pay a mechanic to come look at it so I thought i'd post on here see if anyone might know what it could be.

[Cartoon]

Check or water in the oil. Drop the oil and see what color she is. Also check the oil cap and see if it's milky

[Spaz]

Oil color is normal.
I didnt drain it but I took the cap off and checked the dip stick a couple times and it was all fine.

[Adrian @ SAS]

Pressure test cooling system - (@ about 16psi) - find the leak - if leaking also remove plugs & listen
Tee-Kay test - check for combustion gasses in cooling system
Check spark plugs (for water / oil both inside & outside combustion chamber)
Test leads - need multimeter
Check dissy cap & rotor button

If you discover the engine is dead, replace with good 2nd hand unit as these engines are pretty much uneconomical to repair