Ford Focus runs ok for days, then for no apparent reason it starts running as if it was missing a cylinder or 2 and has to be nursed along? if you stop and sit for 5 minutes it starts and runs fine for no apparent reason until the next time it decides to play up.

I have changed the fuel filter and would like to clean the EGR valve but can not get it out. I have removed the 2 T35 screws holding it in and disconnected the electrics but I cannot pull it out. It looks as if it has never been out and it has done 84000 miles. Does anybody know if there is a tool for removing it or am I going to have to make one? thanks any suggestions welcome.