I replaced my EGR only to realize it was a universal GM unit......."so that's what all those washers were for"...it turns out,that the correct size orifice washer is supposed to be installed into the exaust inlet before the EGR is installed. there's about 20 washers with different size holes,that came with the EGR. it's not that hard to find the right one,all I need is the number from the OE one....whoops!,threw it out already! which will give me the best performance,cover plate or correct sized orifice washer ?? I was thinking of covering it until I can find out the # for the old EGR. right now it's in with no washer,the car is running kind'a soft..like it's leaning out at the top end. thanks for your input. JYD