Been having problem with my 03 Mitsubishi Lancer oz rally I get 2 codes p0171 and p0401 I’ve changed the egr all the lines that are in the egr system also when I check the on board data it’s saying it keeps going in and out of open loop every 5 seconds

 

It sounds like you have a vacuum leak, your manifold is trying to keep a vacuum and its getting extra air probably from one of your vacuum lines causing it to go in and out of open loop and reading lean. Just check all your lines, its most likely not the egr valve or the o2 sensor