TTT
Possible causes:
Plugged cat - affects top end too.
TPS
Insufficent spark / wrong gap. (plugs, wires, coils)
Leak between MAF and TB (gets worse as pressure in intake pipe falls)
Fuel pressure falls (filter, pump, regulator)
MAF sluggish
Spark problems give rough stutter, the others are more like a big loss of power.
