2000 Renault Scenic car juddering

Could be exhaust , exhaust manifold / gasket , coil pack or a combination of all . Plus many other possible causes , need to check it out and eliminate bit by bit .

Get a friend to hold a rag over the tail pipe momentarily whilst you check the system for leakage.

really common is a coil fault.They are prob individual coil sticks so if no diagnostics jus go through one by one try with new coil but is worth changing plugs at same time because the coils burn out due to plugs being worn