OBD code 33, 91 pontiac grand prix

91 Pontiac grand prix 93k miles, upon start
up  it idles normal, then idles pretty high and
check engine line comes on and then engine
starts to surge, always dies at idle, there is
hesitation in accelerating and decelerating
plus after driving a bit on the road the check
engine light eventually goes away but once I
let off the gas it comes back on, brand new
map sensor and iacv, still won't run right
pleas help.