bad running e39

well haven't used the car for a couple of weeks as was doing a few jobs on it when I had time,started it a while ago and it ran bad,would barely tick over and would drop to 500 rpm and cut out.have one of them cheap code readers whichsays p0505:idle air control system.is that idle control valve..car was running fine and I started it regularly but didn't drive it.is the icv hard to get at to clean or any ideas why for no reason its showing up.the eml light has come on as well and the orange triangle..all ive done to it lately is install new radio and im doing the brakes,,one pipe isn't connected but doubt that has any issue connected.any advice appreciated.

Could be vacuum related


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As dave said could be a vacuum leak, if you have a look at the "y" shaped bellows from the air intake to the engine block below the disa valve that's where the idle control valve is, that particular bellows is also the one that cracks and causes the leaks. Removing both is an easy job Gar has a write up on the valve.

Thanks lads.will check car tomorow

Smoke test. Simple... Find your vacuum leak in five ten mins

the issue was camshaft position sensor...