Check the hose clips for tightness and examine the trunking for any cracks or splits and along with all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best pretension to locate a leak is to have the engine executive and warm and subsequently spray can lighter gas /propane or brake cleaner roughly speaking each joint in turn. If the engine rev s going on 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 below par pump will every consequences in insufficient fuel swine delivered to the engine. Might along with be worth cleaning out the idle promptness rule motor / valve as these get clogged up taking into account carbon and some brake cleaner washed through helps free things off.
I don't have any check engine lights unless I unplug the MAF sensor. bearing in mind the MAF is plugged in subsequently the car will stall unless I put my foot upon the accelerator. There is as well as an intermittent popping hermetic coming at idle.