1998 Ford Falcon Hi Name Hani Qld 6 Cylinders Sedan 4 0 Car Surge Only Accelrate

Hi my name is hani from qld i have a ford falcon 1998 6 cylinders sedan 4.0 the car surge only when i accelrate hard on a high reves about 4000 i mean i push it so hard but dosnt do it all the times i change the igntion.coil pack leads spark plugs and fuel filter and engine oil and filter im not i don't know whats wrong with engine and dosn't do it when im driving normall only when i push the engine hard while im driving