Astra x18xe1 engine jerkiness?

My astra is jerky when driving steady & when I slowly accelerate, on overrun/deceleration and when I put my foot down to hard accelerating its fine. I have fitted new plugs air oil & fuel filters, cleaned the throttle vavle with carb cleaner and checked & cleaned all hoses, then I removed the ER valve cleaned & refitted it. Somrtime it seems ok and other time its really anoying when driving steady. I disconnected checked and sprayed most electrical connections (camshaft, crank sensors both ECu plugs temp sensor EGR plug throttle valve plug MAF plug and a 2 pin valve near the MAF sensor with a small hoes at each end). Please advise.