egr

i hooked my egr back up this weekend becuse i definetly got better gas miles with it. the plunger method worked fine when it was removed but now i have a cel with it hooked up. i removed the green and red vac lines that hook up to the egr, intake, and the smog lines when i removed my smog pump. i have plugs in place of the lines. i have not checked codes yet but i will soon. could the red and green vac lines have something to do with it? do you need them or not? thanks

edit
btw this is on a 95. i accidently posted it in here.