Quoting galantrevolution:
on my 91 vr4 the idle bounce from 500 to 900 and i know is runing rich b cause it didnt pass smog, can somebody have the problem before
You need to start typing in a coherant manner. If you aren't then you will find that you get little or no help. This isn't a chat room, were not high schools girls, and we expect some type of decent sentence structure.
As for your problem it coul dbe a host of things. As with any good 4G63 fix start with a leak test and make sure you have no boost leaks. After that make sure your idle is adjusted properly by the VFAQ. If that doesn't work then it could be the IAC has gone out or that your FIAV is dead.
Try a few of those then get back to us.