idle not reaching high enough

[nash8]

I just noticed the other day that when i start my car sometimes it only revs up to like 1500 rpms when it normally goes to 2000. Sometimes it goes to 1500 and sometimes 2000. Right now i have 3 cel codes right now. One is because i got my new ecu put in, another is my fuel pump relay, and the last is either the iac motor or a vacuum leak. Would a any of these problems cause this?
thanks

 

[hkdl]

vacuum leak would cause the idle not going high enough.

My car only idles at about 1000 when warm and 1500 when cold...

 

[nash8]

well i'm guessin thats probably whats causing my stalling too. Well atleast i kno what it is now.
thanks