Space Crusier Spluttering

[lhobbs]

Hi my dad owns a f reg toyota space crusier. He loves it to bits and used it as a family vechical and to carry things. Around 6 months ago it startd spluttering after being driven for about 20 minutes and backing off the throttle for about a minute would soon sort this out. It eventually got so bad that he stopped using it. I used it about 2 months ago just to the village about 5 miles away from me. It actually started spluttering after about 10 minuts and it wouldnt rev and finally cut out only after replacing the spark plugs did it restart. The plugs i took out were ABSOLUTLY black with soot I was able to get home and it was parked up until today when i decided to get it back on the road after a small drive it spluttered up hills and splutterd when trying to rev over 4000rpm. could any body please help me with what could be wrong could it need a good tune and how would i go aboout this.

I am used to deeling with cars but ive never delt with a toyota thanks