hi i have this seat it has a problem idling it starts hunting and cuts out it has 2 fault code one for map sensor & one egr i cleaned & tested map sensor all ok & egr cleaned & blanked off still same the throttle body has been cleaned basic setting preformed, timing is ok. I have smoke tested intake manifold no leaks but on live data on map sensors on idling is 500 should be arounf 300 i think i asked customer if dealer can have a look they say her is a small vacuum pipe under the intake manifold leaking is that true? & where is it just before i attempt to take manifold off why does it not leak on smoke test?. thanx