hopefully this is a quick one,
I believe the issue is in the afm or the ecu at this point
title says it all pretty much, I've been chasing the issue with my s130 where it randomly started running super rich and died while driving
i managed to get it going again and it would die under 2k rpm so I red lined it all the way home
i pulled the engine apart because it needed valve seals and a timing chain, i replaced a bunch of gaskets and checked my compression while I was at it
compression was good across all cylinders in the 145-155 range
i replaced the fuel pressure regulator and have it set at 30 psi idle and 36 cranking
new plugs wires cap rotor O2 sensor and injector seals
none of the injectors are leaking and I disconnected the fuel line to the cold start valve to eliminate that factor
the afm was replaced about 3 years ago now so I have a hard time believing it is the issue
car will struggle to idle at 600 and blow black smoke while it runs, if I cause a vacuum leak it runs at 1900 and no more smoke, and if I turn fuel pressure down to 20psi no more smoke
neither of these things are a solution to the problem and im at a loss so far