Accent LC (2000-05) :: 2001 - Transmission Physically Downshifts Or Locks Up In 3rd When Let Off The Gas

Car is a 2001 Accent 1.6L 4 door automatic with about 130,000 miles on it.

Transmission shifts correctly into reverse, drive, neutral as well as manually shifting into 2nd and 1st. When in drive I will accelerate perfectly through 1st gear, shifts smoothly into 2nd gear then the problem arises. The car will shift ok into 3rd, but if I let off the gas to coast to a light or a corner, etc, the transmission physically downshifts or locks up in 3rd (like driving a stick, ie the car has drag like the converter is locked instead of freely coasting). It feels like 3rd gear but could be 2nd. When I go to accelerate again without coming to a stop the car has this same feeling of drag with no power and speeds up very slowly (almost like i am pulling something behind the car or am in a gear that is too high). If I give it enough gas to force a downshift it really slams that downshift. While the car accelerates through the rpm range after this downshift it will rev past the normal up-shift rpm until it finally slams into the higher gear. Or if i hold the gas steady at the higher rpm the car will suddenly slam into the higher gear. after all of this nonsense the car drives perfect through to OD. The problem is much worse going uphill and is consistent every time it is driven.

Also, sometimes the car would shake and vibrate when hitting the gas during this "drag feeling" until i let go and did it again. This is pretty random compared to the main problem but also seems to happen while the car is in 2nd or 3rd. This has been happening for about 5 months now and as far as i know was sudden. And on another note it suddenly was shifting fine the other day while driving it. I haven't driven it since then but this completely stumped me, as most problems will do when they magically disappear.

There is no check engine light, OD works fine and the car does not go into the safety mode where it will shift to 3rd gear on the highway. It's city driving that is the real headache (2nd and 3rd gear difficulties). Would the pulse generators cause this? bad TCM? i haven't scanned anything yet but will be within the next few days(at pep boys or similar) as well as ohming out pga and pgb. i have found resistance readings for pgb but nothing for pga, what should pga read? fluid is also within acceptable amount and color.

My initial thoughts were dirty or stuck solenoids/valves in the valve body and i was going to do a filter and fluid change with a quick valve body cleaning and check. But after researching on here I am starting to think it may be electrical. The only reason I put my scenario up is because it seems that everybody else who is having a similar problem is also having the "no reverse" or "shifting into 3rd on the highway" problems while i am not. On a random note, for my own piece of mind, how do the pulse generators work? Are they just reading ticks on a gear cog in the tranny or something? fluid flow?