Please help won't rev past 4500rpm

[El Postino]

I'm having problems with my 180 when i fitted my hks dump valve i disconnected the old dump valve that was down by the intercooler and blocked off the the pipes that weren't needed and i disconnected the wastegate valve control solenoid valve aswell it ran well for a while but now she won't go past 4500rpm she just starts to splutter and feel sluggish can anyone help

[adrianfromthecastle]

i'm thinking MAFS

[El Postino]

is there a test i could do to find out if it is the mafs

[480sx]

Im thinking its your MAF too. When they go out they trigger a failsafe that will stop you from reving past a certain RPM to prevent leaning out your engine due to a faulty MAF. Check your FSM, there will be a diagnostic flow chart for your MAF.