Assuming "lock plate" is TCC, this could happen because the TCC doesn't disengage due to opening the throttle from above 0% to something higher. Separately, if the throttle is at something above 0% and the TCC is locked, returning the throttle to 0% will unlock it in anticipation of hard braking potentially stalling the engine.

That'* why we've been talking about your TPS. This is what the PCM looks at for throttle position measurements.

What you are describing sounds exactly like normal behavior. At speed (you confirmed 65mph previously), the torque converter should be locked with relatively steady throttle. This means there is a locked physical connection between the engine and transmission. When this is locked, the engine speed will be directly correlated to ground speed, and will not vary based on load, like it would with the fluid connection of the traditional torque converter. The computer controls this (known as TCC Lockup). It will only disconnect it if throttle is fully released, brakes are applied, there is a heavy throttle demand the engine can no longer maintain, or if the vehicle slows below the TCC lockup speed threshold.

When you would release the throttle fully, and then pick it back up, you met one of the criteria that breaks lockup. If you had the cruise control set, and began climbing a hill, the cruise control would start cranking more throttle in to try and maintain speed, until the excessive throttle threshold is met, and the computer disengages lockup to gain engine speed for more power. If even more power is required, the car should downshift out of overdrive in to third.

Using the brake and throttle manipulation, coupled with the gear selector, you should be able to determine based on engine and vehicle speed exactly what gear you are in, and whether or not TCC lockup has occurred at any given speed. Strategies vary by year, but, for economy'* sake, they typically like to have 3rd gear lockup happen beyond 35mph, and OD lockup by 50mph.

Has there ever been a time when the vehicle behaved properly by your standards? If so, what has changed? Does it require a stupid amount of throttle to break TCC lockup, whereas it didn't before? Was TCC lockup never engaging before, but it is now? Did you begin to notice the vehicle didn't want to pick up speed when you tried pushing it, where as it would before? Was this a one time thing where you went to jump on it to move, and it didn't for whatever reason, and you started obsessing over otherwise normal behavior?

You guys are awesome. It is entirely possible that i'm suffering nothing more than automotive hypochondria or ignorance (or both). I honestly don't remember if it was doing it before and I didnt notice it or if its a new thing. I might just take the old girl down to Aamco and have one of the mechanics test drive it and see what they say and then work from there instead of throwing parts at the car unnecessarily.

Considering the condition the car was in when I got it (it was free so Im not complaining), I can't remember it ever acting properly. lol.

It doesn't require a stupid amount of throttle when I release the gas and reapply. Just enough to get it faster than it was.

I wouldn't take it to Aamco. I've seen them condemn all kinds of small-repair and perfectly fine transmissions. Before anyone bashes me, there are probably some good Aamcos out there, but the bad ones have built a certain reputation. Best bet would be to find a good independent ATRA-affiliated shop that has a bazillion great reviews. If you have a mechanic that you trust get a suggestion from them, then make sure they are ATRA-affiliated and have a bazillion good reviews.