hi foulks basicly iv hit a wall and dont know what eles it could be

its a s2 on standard ke fueling timing bang on and metering unit set at 3.5%

when you rev it up and hold throttle open it gets so far say to 3k then shuts off revs fall and then pick up again and drop ect ect ect............... and keeps doing this never getting any higher revs,

BUT if you disconnect the plug the the black box on the right hand side towards the back on the metering unit it revs all the way round to 6k fine

things i have changed...

metering unit
black ecu
silver ecu
dizzy
tps



any ideas guys as its really got me!!??