2001 escort iddling very rough. - 2001 Ford Escort ZX2

I have the same problem with my ZX2. First you have to find out what engine you have to find out what emission control system you have. if you have a ERG valve clean it and your throttle body. Throttle body cleaner is under 10 bucks at autozone. If you don't have an ERG valve you might need a new idle air control it is 100 bucks at autozone and on the ztec engine it is bolted underneath the throttle body. you should also clean your mass air flow sensor which is located in your air cleaner right behind your air filter, after all of that check all your vacuum lines for leaks and if that does not fix it you might need a new PCV valve this one is pretty cheap about 5 dollars.