this is my first mustang and really dont know alot about cars but do know some stuff but on the egr spacer the vaccum lines are plugged off but its not running it is skipping and poping and will not idle but i think it is a fuel problem but please help with the vaccum lines
the EGR spacer does not have any vacuum lines to it. The 2 nipples on the spacer are for coolant flow. One of the heater core lines should have a hose running into and out of the egr spacer. It's a popular thing to do (plug off the line) and shouldn't impact driveability, though there are differing opinions as to whether it's a good idea.
As far as your idle issues, could be a couple things? Did it ever run right? Did you mess with anything or did it just start running crappy out of the blue. I would go over all vacuum lines and air intake tract, check for unplugged sensors (IAC, MAF, TPS, IAT), timing or firing order wrong somehow, PCV or little screen under PCV jammed up, spark plug wires all where they should be?
need more info on this one. as 5L5 pull the codes and see what comes up. sounds like bad timing or a bad vacuum leak. will the car stay running if you hold the gas?
I would also clean the IAC and if you have mass air, the MAF sensors. I would also check the TPS and look for any loose/broken vacuum lines.
When I first got my car it wouldnt hold idle and would die unless I kept giving it gas to keep the rpms up. turned out I had a broken vacuum line. I replaced that and it ran great.