Engine stutters (Vehicle shakes) with slight accelleration

Common problem with seemingly multiple causes which I myself am gradually going through....HOPING that I don't end up having the most costly... that being transmission/TCC/TCC Solenoid related. Along the diagnosis path I've discovered a Throttle Position Sensor that was bad, a Crank Sensor that had occasional hicups (only showed when I really forced and encouraged the shudder problem), a fuel filter that was dirty, fuel injectors that needed Techron, plug wires that were long overdue for changing (plugs were changed a couple years back and should be fine), checked the ignition coils and found them ok, and engine vaccum can also be called into question. And after all this I have found improvement in the engine's ability to deal with power under load....but NOT solved what is a definately SHIFTING related shutter around 50-60. So the next stop is a transmission repair place which I trust. Everything else I've done myself (which I could also verify the vaccum is fine). So my advice is to do the kind of things that you'd do to "tune up" this engine. Make sure fuel & ignition are happening the way they should be. Then start considering the transmission. Good Luck... I'm no expert...but I've been down a similar road. BUT ass