Regarding the jerking issue, if it isn't running smooth then identify the issue and fix it.
your first priority would be to get a fine spark regardless of timing, get the coil, distributor contacts, cdi(don't know what its called condenser or something but it functions similar to cdi), spark advance mechanisms(vacuum leaks and centrifugal weights/springs), plug wires, spark plugs and grounding checked.
once it is all set your next step would be fuel system which includes fuel pump, air filter (make sure its frypan box is sealed tight and venturi of cng is properly removed), fuel filter, carburettor (jets, float, power pump, vacuum pipes connected to carb / dashpot, a/c and electric load idle adjustment working properly, auto choke not stuck).
a relatively new car not maintained properly is worse than an old car maintained properly
an old car not maintained properly is the worst and would give you nightmares.
I don't really know why you opted for an 11 year old car nor properly maintained old cars are that bad but it seems like you preferred shashka of vxl over a clean vxr.