Hey Normally I publish an article, and 2-4 days later I submit the same post to ezinearticles.com... Is that ok and not hurt the rankings (because of duplicate content) or is it having a bad influence on the rankings?
Why not publish your article on your site first, then go to article sites and write about your article and refer to it with a link to it on your site. That way you drive traffic to your site and people will usually take a look to see what else you have there. They may then become a regular visitor to your site or subscribe to your feed
it can be seen as dublicate content so be careful, something else you can do is write some of it on your own site and some of it on the articles site.
Another problem you may face is the ezinearticles page outranking the article on your own site. They likely have more authority than your own site. It may be best to modify the article first.