My 1996 cougar doesn''t have reverse or neutral. Both reverse and neutral drive forward instead of what they are suppose to do. The trans. seems to work properly though when hooked up to a computer by a mechanic. What could cause this?

the linkage from the shifter to the trans is too tight or hung up on something and needs to be fixed. sounds like it''s actually in neutral when you have it in park.

Well it also starts going forward in reverse and neutral without giving it any gas, can that also be because of the linkage?

It can''t be the linkage because underneathe u can see it shifting into the gears

I didn''t say the linkage was broken, just in the wrong position. unless you know that the position that it''s in is supposed to be in specifically for each and every gear, then the position may need to be adjusted.