Just thought I'd mention this as it's more common than you might think.
I have a VIS which is now fully recommissioned at great expense.
I noticed it wasn't really pulling as expected above about 5500RPM. Looking at the specs for the engine peak power is delivered at 6700RPM which suggests the engine should be a proper screamer.
Anyway I disconnected the Mass Air Flow Meter and gained about 30bhp and I promise I'm not exaggerating. As the ECU learned it got faster and faster. Feels more like 170bhp than 152bhp!
Ordered a new MAF meter today.
My mate had a Marea and he had the exact same experience with that. Definitely worth unplugging the meter and see if you gain any power.
Edited by OnlyItalian (09/01/2019 13:00)
"Proud owner of LE141 and a 99 VIS broomie "