Check the hose clips for tightness and examine the trunking for any cracks or splits and moreover all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best quirk to locate a leak is to have the engine processing and hot and then spray lighter gas /propane or brake cleaner going on for each joint in turn. If the engine rev s stirring you ve found your leak.
Its along with worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not a hundred percent pump will every repercussion in insufficient fuel living thing delivered to the engine. Might as well as be worth cleaning out the idle speed rule motor / valve as these acquire clogged going on similar to carbon and some brake cleaner washed through helps free things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you in the works to date upon all maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms up and is warmed up? oftentimes in engine be in many factors may cause the similar symptom(s)