I've replaced all my vacuum lines that I'm aware of since most of them were dry rotted when I got my 88 Supra with a 7mgte motor and it helped some what with my vacuum problem but not nearly enough. If im cruisin along and my rpm's are anywhere at 3 grand or above and I push the clutch in to get ready to slow down, sometimes the car will die so I have to just slow down using the brake while still in gear and let the rpm's fall to about 1 1/2 or 2 grand and then take it out of gear. Also when it's idling in place after the car has warmed up, it has a bunch of faint poping in the exhaust like its cutting in and out real fast. You can really hear it if your standing by the muffler and also you can see the tac needle move with each pop. Does anyone have advice on the matter?