Change oil
Make sure the engine is HOT- drive for @30 minutes BEFORE the test.

Check timing
Check cap rotor
Check wires

Check the valve adjustment-
I did ALL the tune up procedures and failed two times, what worked for me was
to readjust my valves.
I had changed a lot of different items and when I adjusted the valves to .00
preload, I passed emissions.

Check for vacuum leaks- ANY leak will cause an increase in the fuel pressure
and could cause excessive HC's- A valve leak will cause a REDUCTION in the
vacuum the engine can produce at idle.

Check that the throttle switches are working and causing the computer to
switch to idle mode, no click, no idle mode.

From all my working with tuning my FI system, there seems to be a delicate
balance of ALL the FI parts working in harmony. If one part is slightly out
of spec or has failed or is out of adjustment there are running problems.
The system will work, might even "run good" but not be right for optimum
running or have various problems.