1991 Celica Gt Four

August 10, 2009

hi i own a toyota gt four 1991 which when booting the acelerator pedal the engine coughs and spluters. this apears to happen at higher rpm, i have recently removed the cylinder head to replace the head gasket, and noticed this engine is fited with ? 4 buterfly valves in the inlet manifold, which i beleive is controled by a vacum diaghpram, to give it botom end torque at low rpm... my question is if these valves do not open corectly eg remain closed how can i diagnose this to be the fault... as they are as (stated) inside the inlet manifold ? the spark plugs when removed are sooty black as if over fueling or air starvation ??? it has had new plugs, air filter and i have swoped the disy cap, rotor arm, ignition coil, from my 2000cc mr2 which runs fine .i have also tried adjusting the ignition timing, and the boost valve for the turbo... ps i was extermely careful in making sure i timed the new cam belt corectly. but however there are lots of small vacum pipes fited behind the inlet manifold and to the best of my knowledge are fited to where they suposed to be.... but not having any workshop manual to refer to can only hope i got it right ??? does any body know where i can buy one from also what diagnostic code reader can i buy which will analys this engine??? any advice would be most apreciated as this car is driving me round the bend trying to put it right . thanks for reading dan....