Hhmmm...You could try a idea I learnt with my old V6 Hilux Surf.
You get some morleys upper cylinder lube or similar (old timers used to use brake fluid i think)
You find a vacuum pipe that goes into your intake plenum,Start the car up ,slowly pour in & let the vacuum suck up the solution,but not to much or too fast,dont let it stall the engine.once you are happy that you have got a little bit in there.Shut off the car.leave it for 15-30 mins.
Then start her up & watch the smoke fly,
Its like a steam train ,so best not done in a public place.It will take some time to clear,some say a good thrashing through the country is good.
The theroy is that the smoke is all the old carbon deposits that build up in the intake etc.
I did it to my surf with no ill effects & funnily enough I also did this on my carbed sprint yesterday.(easier because you just put down the carbs),& it worked well.
Its is reccomended that you replace or clean your spark plugs afterwards.But not absolutely imperitive.
Try this at your own risk,I was very nervous the first time, but it really is easy.As long as you dont put so much in, that you hydrolock the engine( dont pour so fast that it stalls).
Helps to but some in the petrol tank aswell,as per normal .