Check the hose clips for tightness and examine the trunking for any cracks or splits and also every the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best habit to locate a leak is to have the engine government and warm and subsequently spray lighter gas /propane or brake cleaner not far off from each joint in turn. If the engine rev s up you ve found your leak.
Its plus worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a in poor health pump will all repercussion in insufficient fuel beast delivered to the engine. Might with be worth cleaning out the idle eagerness direct motor / valve as these acquire clogged up subsequent to carbon and some brake cleaner washed through helps pardon things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you happening 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 conduct yourself many factors may cause the same symptom(s)