sounds like exactly what mine did.

turned out to be the ajustment of the TPS. with the ignition switched on and the cover off the ecu multiplug, go across pins 17 and 30 and you should ajust the position (via its elongated holes) until you read 0.2 - 0.25 VDC back at the ecu with a multimeter. you will need to take the intake pipe off and undoo the 4 small bolts around the tps housing to get it off and access the elongated slots for the tps.