So going back to your original post. Instead of holding the P switch, jump terminal 5 to 6 on the comparator board, this will let you run temporarily while testing. Be sure to remove the D010 wire so the doors can't open. You said the car runs down slowly, on up inspection. With a DCV meter + lead on Test point 3(wire 208) and - lead on TP 12(wire 121) you should have a positive voltage in the up direction. This is the tach circuit. It almost feels like you are missing a voltage or a contact somewhere in the circuit. Another check is at wire #187 TP-2 to wire #121 TP12. you should have, with the black lead on 121 a neg. in the up and a pos. in the down. TP-2 is fed with U and D contacts. Also, loose connections at terminal points will cause many hard-to-find problems. It would be wise to go over all connections. Good luck.