Renault Clio Engine Fault

Renault Clio 1997 1.4 8v single point injection. 30,000 miles. Hey guys when the car is pulling away or accelerating from low revs it judders as about to stall. Even with the throttle fully depressed I initially thought it was the ignition system and since new ht leads rotor arm cap and plugs I figured coil. After I changed this it did appear better for bout a week. Now its doing it again and im thinking fuel. I have had two occasions when the car struggled to start. Im thinking sum sort of sensor any ideas?