86 5.0 Mass Air Conversion HELP! Do I have cruise?

Look on the trans where the speedo cable goes in. If there is a sensor on the cable there is a pretty good chance it had cruise at 1 point in time. If you do some searches on here I am sure someone has posted on this issue before.

Even if there is no sensor the harness should still be there, so you could still get the wire colors.

You may have some stall/return to idle problems as you slow down and a code 27 or 29 which are indicators of a malfunctioning VSS. I would give a try disconnected and see what happens.

Try it now without running any wiring changes, and if it doesn't work for you, then make the wiring changes to add the VSS.

Here's some electrical help specific for the 86 Mustang:
See http://slantnosefox.com/picturehosting/jeremy/86 electrical & vacuum troubleshooting manual.zip you can download the whole set of electrical troubleshooting and diagrams for an 86 Mustang courtesy of Jeremy, AKA V8only.
It is a big 61 MB download that you get to unzip and save on your computer. It may take some time to download it, but the results are worth your time.

I converted my '86 to mass air. The new ECU requires a signal from a VSS. IF you don't or can't install one in the tranny you have, there is no logic in even bothering running the wires from the ECU to the VSS that is just hanging there not attached to the tranny.

Like mentioned above, without the VSS signal, you will throw codes and may have some decelleration/stalling issues. Your best bet is to try it without the VSS and signal wires hooked up and actually see if you have any stalling issues. If you have no problems, drive it that way.... if you do, though, you will have no choice but to figure a way to install the VSS on the tranny you have or get a tranny that you CAN install a VSS to.

And yes, the VSS signal wires on an '86 are a different color than what they talk about on the installation instruction sheet of ANY mass air conversion kit I've ever seen. It's like they have just completely forgot and/or disregarded that the '86 model year is different from all other years.

You're on your own when it comes to figuring out which color goes where to the ECU. I had to look at an '86 wiring schematic and figure out which one was the power in wire and which one was the signal out wire from the VSS, then put them in the correct pins of the ECU. I have mine all taped up and can't see which ones I used or I'd tell you... you'll just have to figure it out like I did.

It just pisses me off that companys that sell mass air conversion kits don't include a seperate wiring schematic for the '86 model... they just assume everyone owns an '87 or '88.