you simply make a little jumper using wire ( i use speaker wire) with wire open on each end. Look behind the drivers side strut tower for the eec test connector. you will see a two plug looking things. one will be a single wire/plug, while the other will have multiple wires. Plug one end of the wire into the single plug, and then plug the other end into the smaller side of the big connector (there is only two wires on this). here is a diagram for the bigger connector. the plus sign is where you need to jump it to the single plug. post back with what you get. The light will flash the number of the codes. i.e. two flashes pause two flashes is a 22. Good luck....
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ok this is what i got, after i turned koeo it paused then did 2 quick flashes. then it did 6 flashes, then 7 then a long pause then 6 flashes then 7 again. it repeated 6,7 twice. Ok then there was another l;ong pause and it flashed once then it paused again and flashed again. I am pretty sure that those two flashes was the seperater between soft and hard codes. anyway then it flashed 8 times, paused then flashed once. then it repeated 8 flashes then 1 again. So does that mean i have code 67 and 81?
67- clutch switch circuit failure, neutral drive switch circuit open; a/c (which i dont have) input high, manual level position (mlp) sensor out of range
81- secondary air injection bypass am1 solenoid circuit failure.
Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or the A/C was on when you ran the test (it is supposed to be off). Possible neutral safety switch or wiring problem. You can generally ignore this code, since it has no effect on engine performance. The code will affect some of the engine running diagnostic tests the computer can do if requested.
Code 81 – Secondary Air Injection Diverter Solenoid failure AM2. The secondary air diverter valve isn’t working on the Thermactor Air System (smog pump). Look for broken or missing vacuum lines on the solenoid valve to the diverter valve. Look for +12 volts at the Red wire and look for the Lt Green/Black wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the LT Green/Black wire for the solenoid valve.
I never heard of a gulp valve. There is no such thing in a Mustang if you go by the Ford terminology.
The Thermactor air pump (smog pump) puts air into the heads when the engine is cold and then into the catalytic converters when it is warm. The Thermactor control valves serve to direct the flow. The first valve either dumps air to the atmosphere or passes it on to the second valve. The second valve (diverter valve) directs it to the heads or the catalytic converters. The air serves to help consume any unburned hydrocarbons by burning them up.
Here's a book that will get you started with how the Ford electronic engine control or "computer" works.
Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst :ISBN 0-8376-0301-3.
It's about $20 from Borders.com see http://www.amazon.com/ . Select boo...very good, and I found it to be very helpful.