I have all of the symptoms of air in the brake system in my 91 and cannot seem to get the air out(New calipers, master cylinder)I recall a post many month's ago that stated that if air is in the ABS unit there is a certain technique to be used and/or it may be a dealer task. The ABS now doesn't run through the test cycle when it is first started and reaches 3mph, but now cycles after about 7 minutes of driving. Sound familiar anyone??

 

This is from my 93 Service Manual:
Important
If the entire brake system must be bled, the master cylinder prime pipe should always be bled first to obtain proper results.
The prime pipe must be bled at the modulator valve in the left rear storage compartment. Be sure to protect the vehicle inter/exter to avoid damage from fluid spilled. Be sure to wipe up excess for bottom of compartment.
The master cylinder prime pipe must be bled anytime the MC or resevoir is replaced. Also, if the reservoir fluid level becomes too low from a leak.
1. Fill MC to proper level (leave cap off during bleeding).
2. Open left rear storage compartment. Remove sound insulator pading.
3. Remove bleed screw cap and place a proper size box wrench over the prime pipe bleed screw.
4. Install a short piece of clear tube over the bleed screw. Put the other end of the tube in a clear container.
5. Open the bleed screw and allow fluid to flow into the container. Allow fluid to flow until all air is removed.
Tighten
Prime pipe bleed screw to 12 N-m (106 lb. in).
-Be sure it seals.
-Replace bleed screw cap.
6. Install sound insulator pad.
7. Close storage compartment cover and secure.
8. Fill MC reservoir to proper level and install cap.

There is more on doing the master cylinder if air is known to exist in it, before bleeding any caliper.