Check the hose clips for tightness and inspect the trunking for any cracks or splits and moreover all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best way to locate a leak is to have the engine government and hot and next spray lighter gas /propane or brake cleaner vis--vis each joint in turn. If the engine rev s happening you ve found your leak.
Might furthermore be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a fast deformity find if you unplug the meter and govern the engine without it. if the engine condition is the thesame then chances are the meter or the membership to it is faulty. Its moreover worth cleaning the MAF sensor wires, as they can get coated in the same way as dirt higher than epoch which subsequently offsets the reading. Use some retrieve cleaner or brake cleaner to spray onto the wires to remove the dirt upon no account adjoin the wires behind everything as they are definitely fragile
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you happening to date on all maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms in the works and is warmed up? oftentimes in engine enactment many factors may cause the similar symptom(s)