2003 Focus SE 2.0 split port Idle surge

I have a 2003 Ford focus with the 2.0 split port engine, It likes to surge when its idling almost like it's trying to stall itself I've replaced the pressure feed back sensor and the u shape hose that goes from the top of the valve cover to the air box. Has any one had this issue and If so what was it the cure to fix it
Oh dear not the dreaded SPI motor. Honestly I would just sell the car lol. I had a 2003 and it was nothing but problems. Have you check the plugs and coil?