I had the 0456 three times, I cleaned out the check valve and I cleaned the rubber gasket and it hasn't come back. No need to spend money if you can fix the problem with a little elbow grease.

And a 96 5.9 Jeep? Did you swap it, or buy it swapped?

 

yes this is true, but you do have to do somthing to fix the problem, not just reset the computer, i tryed the same thing with my gas cap, didnt work, threw the code a month later, guess the way i look at itid rather spent a bit of money to FIX the problem rather than put it off till later...

as for the jeep it had had a 5.2L blew it up now i have the 5.9, realy the two motors seem about the same in it wish it was a stick that would be sweet...gas sucks tho! i like my 4.7 the best overall

 

on another note did ya fix the oil problem?