I have a 97 discovery xd pulled the codes it said I had #2,#7 injector miss firing and I had y pipe issues. so the first thing I did was pull the y pipe and did notice it was bad replaced with new one replace both injectors. problem I am having at idle it runs fine once you hit the throttle it miss fires and sputters checked the pressure at the rail it is 38-39psi what do I need to check running out of options here