i have a 96 vw golf with 1.8l engine runs good when cooled and when it warms up and comes down from fast ideal it pucks through ext and will jump form like 800 rpm to 400 or 500 rpm and sometimes die but will start right back up i put new plugs,wires,dist cap and rotor button adjusted the timeing put some injector cleaner in it no change any help would be a help