Spray that carb cleaner into those small hoses and around the engine, intake manifold. Any place that has a vacuum lake will suck the carb cleaner and it change the idle, also you can also put a small vacuum guage on the oil dipstick tube to check an internal vacuum leak coming from the intake gasket.
By the way, have you check your PVC lately, if you shake it and it rattle still okey if not replace it or maybe the MAF sensor is dirty.