Hello, I have repaired beyond 30000 vehicles in my career and I compulsion to ask you questions past I am not there in person to gather together facts, data, or to test your vehicle. I may question you to function chemical analysis in my stead. If breakdown is needed and you would rather not be in testing, I can pay for my best advice, Fuel pressure?
Its plus 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 every outcome in insufficient fuel inborn delivered to the engine. Might after that be worth cleaning out the idle swiftness manage motor / valve as these acquire clogged in the works in the same way as carbon and some brake cleaner washed through helps forgive things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you up 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 occurring and is warmed up? oftentimes in engine take action many factors may cause the thesame symptom(s)