1991 Mustang - Idle Problems with no codes

I had posted in another thread and jrichker suggested I start a new thread for the discussion. I have a 1991 LX Convertible 5.0 that has had an engine swap back to a stock 5.0 (it's a long story but suffice to say there will be an upcoming project). I am having trouble pulling codes using the method posted by jrichker (a method I have used successfully many times in the past and I just used on my 1995 F 150). I have a 1991 LX 5.0 Convertible and I the specific problem that I am having is that it shuts off when I push in the clutch or come to a stop, not always just most of the time. When following the analog meter method to pull codes I get nothing, but I believe something is amiss and here is why. When using this method, http://www.troublecodes.net/Ford/, on my truck I get codes. The difference is that when the analog meter is hooked to my truck it reads 12 volts until the key is turned on and then it drops to 0 to begin the code sweep sequence. On my Mustang, it reads 12 volts when connected but it does not drop to 0 when the key is turned on and never sweeps the needle at all. I then read the thread below that was suggested by jrichker and hopefully we are on to the problem. According to the article:

"With the power off, measure the resistance between the computer
test ground (black/white wire) on the self test connector and battery
ground. You should see less than 1.5 ohms."

While I do have less than 1.5 ohms it practically an open circuit (much less than 1.5 ohms).

See http://forums.stangnet.com/showthread.php?t=608084 for help.

Looking for help.

Thanks

Sorry it has taken so long to respond but when i was coming back up from my shop to get a meter to continue the checks, I completely tore my calf muscle and have been on limited standing time for a while.

Yes, I did make the measurement with the power off although I did not disconnect the battery, I will do that this morning. I think my problem may be related to a ground issue, but I am not sure. I will perform the test on my 1995 F150 to have a benchmark to go against and will post the results shortly.

Thanks for your help

Okay, results time. I disconnected the battery and it reads an open circuit. I performed the same test on my truck following the same procedures and i get a reading around .9 ohms. This leads me to think I have a ground problem (maybe). Is there supposed to be a ground wire for the computer itself? Where should I go from here?

Thanks to all

Step 1: With the power off, measure the resistance
between the computer test ground (black/white wire)
on the self test connector and battery ground cable.
You should see less than 1.5 ohms.

Results: I have no resistance what so ever (meter reads OL with no beep indicating a closed circuit).

Step 2: If that checks good, remove the passenger side kick
panel and disconnect the computer connector. There
is a 10 MM bolt that holds it in place. Measure the
resistance between the STI computer self test
connector (red/white wire) and pin 48 on the
computer main connector.

Results: The resistance reads approximately .8 ohms.

While I have the connector off of the computer,
I decided to measure the resistance between the
computer test ground on the self test connector
and pin 46 on the on the computer connector and
I have about 1.1 ohms. This makes me wonder why
I receive no reading when the connector is
connected to the computer.

So, if I have no resistance reading in Step 1 and approximately .8 ohms resistance in Step 2, what now?

Thanks

Okay, just for grins, I had the parts store give me a new computer and I still have the same results. Please, someone help.

Thanks