307 2.0 petrol fault

[d.kenny]

have a problem with my 307

its a 2.0 petrol

under load the engine misfires and gos to die but when you ease the revs of the throttle up the revs build ok

tried the common things

plugs

coil pack

also tried on a new throttle body as the maf is inbuilt as i thought this maybe at fault but still no better...infact with the second hand part it was worse

iv dropped the exhaust off even to eliminate a problem with the cat and still no better

can anyone suggest if there are any common faults with this engine and does the knock sensor or anythin like that have any blame?

any input would be much appreciated...cheers