Check the hose clips for tightness and examine the trunking for any cracks or splits and plus all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best artifice to locate a leak is to have the engine direction and hot and later spray lighter gas /propane or brake cleaner going on for each joint in turn. If the engine rev s occurring 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 under the weather pump will all repercussion in insufficient fuel beast delivered to the engine. Might as well as be worth cleaning out the idle swiftness rule motor / valve as these acquire clogged taking place in the same way as 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 in the works 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 stirring and is warmed up? oftentimes in engine play many factors may cause the similar symptom(s)