Just bought a 2013 zforce 800 ex. Gave it a service as the acceleration from standstill was jerky. Get this, spark plugs were finger tight I couldn't believe it, but it hasn't cured it. If I'm moving and accelerate it's perfect. If I'm sitting still at traffic lights etc I have to gently feed the power on, if I put my foot down it pulls away sharp. If I use between gently accelerating and full throttle it jumps and jerks about, classic kangaroo petrol. I just wondered if anyone else has this problem, or anyone who's fixed it, maybe it's normal??