Need something cleared up
#11
I skimmed over that part before. So a previous owner then converted your car over to an automatic? Could have slapped in one that was already on it's last leg. Also, not hooking up anything to make the torque converter lockup can burn up the trans. The internal fluid pressure is designed to flow a certain way once the t.c. locks up. Take a look see if there is anything plugged into the lockup solenoid connection on the side of the trans. Sounds like a shlock "shadetree mechanic" may have been putting his hands where they didn't belong.
#12
Could be a goof with the decoder. Get under the car and look up at the trans tunnel and see if there are any signs of it having had an opening for the shifter. No trace, no manual trans.