Hello all, my car is a 2013 Subaru BRZ/Scion FRS with 166K miles. Car has not been running well, it sometimes feels like its about to stall out in idle and drops to 500RPM and engine shakes. When I give the car some gas the RPM jumps up and down. I replaced intake manifold gasket, gaskets for fuel injectors all replaced, fuel pump & fuel filter, mass air flow sensor, PCV valve, spark plugs & ignition coils replaced... I don't want to keep replacing parts and guessing at this point. Only code that pops up is for a p0172 for running rich. When I go for a test drive to test it sluggish at acceleration. Any suggestions would be helpful. Thanks everyone!