Now you might think that spraying lighter gas going on for a hot engine isnt wise, however the flash /ignition reduction of gas is roughly 400C thus you infatuation a naked fire or spark to set it off and Ive used this method for many years without incident. function your quirk through each viable joint one at a times and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to offer a spraying wand and allow a talk to blast of gas into each area, especially those hard to attain in imitation of large implements.
Its next worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not at your best pump will all consequences in insufficient fuel innate delivered to the engine. Might along with be worth cleaning out the idle swiftness direct motor / valve as these acquire clogged going on taking into consideration carbon and some brake cleaner washed through helps release things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you going on 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 up and is warmed up? oftentimes in engine function many factors may cause the similar symptom(s)