x reg 1.6 skoda octavia lcaking power please help

hi im just wondering if someone can help my Skoda Octavia lacks acceleration i've replaced the clutch and head plus head gasket (head gasket went)the timing belt has been timed and tensioned properly but it still lacks power plus i have to pump accelerator to get it to start properly and when i put my foot to floor a it takes forever to build up the revs at standstill and when moving. i've had it on a diagnostic machine but only things that came up was map sensor was intermittent (which i have changed) and basic settings wasn't performed the engine code is aee so if anyone can help shed light on what it might be that would be greatly appreciated thank you