Have you tried resetting the idle?
Condensed from the service manual:
(1) Before starting the inspection and adjustment procedures,
set the vehicle in the following conditions:
- Engine coolant temperature: 80 to 95°C (176 to 203°F)
- Lights, electric cooling fan, accessories: OFF
- Transaxle: Neutral (P range on vehicles with automatic transaxle)
- Steering wheel: Straightforward position
(2) Connect the scan tool to the data link connector (white)
(3) If not using the scan tool, proceed as follows:
1) Insert a paper clip into the l-pin blue connector as
shown in the illustration.
2) Connect a primary-voltage-detecting tachometer to
the paper clip.
3) Using a jumper wire, ground the diagnostic test mode
control terminal (terminal (10)) of the data link connector
(white).
(4) Remove the waterproof female connector from the ignition
timing adjusting connector (brown).
(5) Using a jumper wire, ground the ignition timing adjusting
terminal.
(6) Start the engine and run at idle.
(7) Check the basic idle speed. - Basic idle speed: 700 + 50 rpm
(8) If the basic idle speed is out of specification, adjust by
turning the engine speed adjusting screw.
If you don't have a service manual, I HIGHLY recommend you get one, you can get them on EBAY on CD for about 15, or if you come to the texas gathering, I usually have a few extra copies to give away.