05 mariner, 3.0 v6 2wd
 

My mariner is throwing 4 codes, p0405 (dpfe egr sensor) , p0351/0353/0354 (ignition coil a, c, d primary and secondary circuit) the car died driving on the highway, took a bit to start it back, now it idles rough and I can hear a vacuum leak but can't trace it down. First reading showed all 6 coils were bad, reset and ended up with just c, now, I've got three. Horrible gas mileage, very sluggish and at this point it won't go more than 45 mph downhill. Any suggestions? I've replaced all three coils which was expensive and didn't do any good and was told that there's a problem with this year make model frequently showing false readings on the egr. How do I find out if its false and what to do now????