you can retract the codes from the SMEC, without a reader.
Look for the diagnostic codes on the web and you'll find what you need.
the basic procedure is turn the ignition on-off-on-off-on and leave on, then count the engine light blinks..
You probably have a bad idle air control valve, or throttle position sensor.
Don't rule out a weak fuel pump or clogged catalytic converter.
Slantsixness