North star engien 2000- 2005 high idle

I have an 03 deville. Started this high idle thing so I did clean throttle body and iac Then recently the Check Engine Soon light came on and stays on and it is doing the high idle thing almost all the time now After reading the posts I first disconnected the battery to let the system reset. No change. Then I sprayed some brake cleaner around the plenum while it was running and it slowed the engine idle it looks like I've got a leaky plenum.the plenum is the connector between the throttle body and intake manifold and there is literally NO way to remove it . so i decided to buy from amazon  
Plenum Coupling Rubber & also changing Mass Air Flow Sensor