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I'm not sure why fordfuelinjection.com says to jump the STI to the negative battery. Sure it works, but all you need is a paperclip to jump the STI to the Signal Return wire on the 6 pin diagnostic connector. See this: http://www.thorssell.net/hbook/eectest.html . You don't need the test light or volt meter in those instructions, just watch the check engine light in the dash.
I have used the paperclip method in the past. It works, but it is really tedious. I think that could be used to diagnose the slightest hint of ADD. It took me at least five tries to make sense of my scribbles after staring at the engine light.
When my truck started throwing codes a week ago I decided to get a reader to have around, instead. I found the Equus 3145 for $29 on Amazon - free shipping, too. This may have been one of the best tool investments I have ever bought. Using the Equus is MUCH easier than counting light flashes. The reader also comes with a booklet that gives clear instructions for each of the three tests - KOEO, KOER and dynamic balance - and has a chart of what the codes mean. It also has instructions for setting up the truck to test all the relays and sensors.
Don't be fooled by the Ford ODB1 "reader" made by Actron that Advance and AutoZone have in the store. It is nothing more than a beeper and will give you no more help than the paperclip.