The following symptoms have presented themselves:

1) One day I had an engine stumble at a pretty specified point in the throttle (seemed throttle position or load-related as opposed to RPM or speed). I could hold the throttle at that position and the engine would stumble and not accelerate, but any more or any less throttle and it was smooth. This problem was consistent for one drive cycle and has not presented itself since, but the other issues below remain.
2) Engine not entering deceleration cutoff mode (DCO). When you lift off the throttle under load the fuel injection should shut off, air fuel ratio should go to infinite (I have a wideband O2 meter) and vehicle should decelerate. This isn't happening, I lift off the throttle, vehicle coasts like an automatic (it's a manual) and wideband stays at 14.7:1 AFR.
3) Occasional inconsistent idle. Sometimes it decides it wants to idle high, particularly when cold. It used be consistent.
4) No CEL has been presented.

Otherwise, vehicle runs like a dream and goes like a raped ape. I'm thinking all signs point to TPS, particularly when I read this about fuel cutoff mode:
Deceleration enleanment or fuel cut-off mode – is reached during periods of deceleration. In this mode, the ECM simply reduces injector pulse width or momentarily shuts the injectors off in order to reduce high emissions and engine backfire. The main signal inputs to the ECM for this mode are the TPS, RPM and the VSS (vehicle speed sensor). This is the reason why a faulty TPS signal that shorts to ground intermittently can send the system into fuel cutoff mode, creating a drivability concern. And, during this condition the ECM reacts as a closed throttle deceleration condition. Another common fault relating to this mode is in systems with an idle switch, whereby, the idle air bypass screw is set too high and the engine idles up-and-down between 900 and 1500 RPM. The reason for this is simply that the ECM is receiving a closed throttle signal (from the idle switch) and the idle speed is raising above normal, causing the ECM to cut injector pulse (injector cut-off mode). To solve this problem, adjust the idle air bypass screw, unless there is large vacuum leak, in which case repairing the vacuum leak will solve the problem. Once the TPS or idle switch signals the ECM of a closed throttle or idle condition and the RPM has dropped bellow a preset value, the system goes into idle-mode. There are other possible reasons why an ECM would activate the fuel cut off mode. For example – If the engine were to reach a pre-programmed high engine speed (high RPM), the ECM would cut injector pulse to protect the engine from damage. Also, if the vehicle reaches a pre-determined high speed, for safety reasons, some systems would momentarily cut fuel and ignition to protect the driver from damage.

A new TPS is $52, so I'm thinking I will start there. Boost gauge shows 20 in vacuum at idle, so there is no vacuum leak. Could also be idle air controller according to the above, but I'm thinking my symptoms align with TPS, yes?