help bad idle

[Serge]

i need some help i have a bad idle fluctuate from 800 rpm to 500 and does not stole but idle ruff and pick back up. so i change my IAC sensor change the throttle position sensor, clean the mass air sensor and throttle body, EGR 2 year old. there no engine light.
when i drive it drive amazing only when i stop it idle bad.
WHAT COULD CAUSE THIS

 

[89silverbullet]

How long ago did you replace the iac? And did it change your symptoms at all? Are you experiencing a misfire?

 

[Eatonualive281]

Well, for starters, check your vac lines for leaks. check your plugs check your coil packs for any fouling or visible damage.

 

[96gt02]

sounds like a vacuum leak to me