Blah...
On a 5spd car, there are TWO neutral switches, one on the transmission and one on the Clutch pedal.. they are closed when ever the shifter is in the Neutral position, or the clutch pedal is Depressed and Open other wise..
NOW the Clutch pedal has a Starter interrupt circuit which does just as the name implies, where as on a AOD car that same circuit also does the Neutral/drive switch function for the EEC.. Which has a spice on the transmission side of the tranny harness, on the switched side of the Neutral park switch circuit.. that then goes back to Pin #30 (on both 5spd and autos) which is labeled NDS
also Pin #30 (NDS) looks for a GROUND to see if it's in Park/Neutral.. which is one reason (of 2 i know of) that the start sileniod on the fender Diode in it, specially on Automatic cars.. on 5spd, it's an ABS only thing (reason 2) and on the 5spd, Pin #30 (NDS) gets it's ground signal from the Signal return Pin on the EEC (sorry forget the pin#)
And from testing on my '91 XR7 (5.0L, Automatic) and against some well known EEC turner on there, i have found that the EEC does alter Timing and Idle speed (only did it at idle) when the EEC sense it was in `park' it had like a 800-850 idle, and like 25-30 degrees of advance timing, i pulled the Red w/Blue wire off the start Sileniod (fender one) and the Idle dropped @200rpms and Timing dropped to Near Based timing (Base at the time was 10degree, and it went down to like 11-12degrees??) Also Had the ABS light come on when i disconnected that wire
This May be totally different with a 3.8SC 5spd computer, since this was done on a 5.0L Auto computer (L1C, AKA modified SC EEC so rumors have been told, if they are still true today i don't know)
Also the Hole dash pot thing may be it too.. it may have different programs when decelerating in gear as awhile as `freewheeling'/out of gear..
More info then you needed? confused yah??
Sorry when i did my 5spd swap on my '91 like 5-6 years ago.. i wanted to know EXACTLY what each circuit did and how it was different between the 5spd and Auto, Anal, yes, but i wanted to do it RIGHT