Check the hose clips for tightness and inspect the trunking for any cracks or splits and afterward every the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best pretension to find a leak is to have the engine direction and hot and next spray can lighter gas /propane or brake cleaner around each joint in turn. If the engine rev s going on you ve found your leak.
Might as a consequence be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can pull off a quick irregularity locate if you unplug the meter and run the engine without it. if the engine condition is the similar after that chances are the meter or the link to it is faulty. Its with worth cleaning the MAF sensor wires, as they can get coated in the same way as dirt more than time which next offsets the reading. Use some way in cleaner or brake cleaner to spray onto the wires to separate the dirt on no account be adjacent to the wires later whatever as they are totally fragile
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you stirring to date on every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms going on and is warmed up? oftentimes in engine statute many factors may cause the same symptom(s)