My TPS has the hole drilled in it. Can’t say how prevalent this is.
How exactly the DME responds to various situations is a bit of a black art. There isn’t consensus on this and I’m no tuner. Best I can do is state what I believe to be true.
The DME has a variety of 3d “maps” that determine injector duration and ignition timing. The 3rd axis is volume of air coming in. The values for injector duration and ignition are also modified by coolant temp (big variable), ambient temp (small variable), O2 sensor info (adjusts fuel trim), and probably another thing or two that I’m forgetting.
Rob Eskew’s boss, name escapes me, has good insights on this sort of thing. He and I aren’t in complete agreement, but his take might be more accurate than mine.
Under partial throttle conditions the DME sets injector duration and ignition timing based on all of it’s inputs. Remember those 3d maps that control the engine management. This is called “closed loop” operation. Under some conditions tho, the DME quits listening to a lot of it’s inputs, and kind of blindly tries to operate as best it can. Think of it as suddenly becoming dumber. This is called “open loop” operation.
During open loop operation, the only variable that the DME listens to (IIRC) is coolant temp. That said, the DME also uses the latest fuel trim info, so if your fuel trim is goofed during partial throttle, it will remain goofed for WOT.
A couple things can trigger open loop. 1) AFM door completely open. I’m told this happens around 4500rpm. 2) TPS signaling WOT. Seems like there’s a 3rd thing but it’s not popping into my head.
So the TPS is one of a couple ways that triggers the DME to go to closed loop operation.
TPS also tells the DME that the engine is idling or is at partial throttle, but for us the important thing is that the TPS tells the DME that you’ve just gone to WOT. This assumes that the DME hasn’t already figured it out by the fully open AFM door.
Impact of a broke-dick TPS. If the above is correct then the only way that the DME is going to know that you are at WOT between 3500-(~)4500 is the TPS. Therefore I would expect a broke TPS to affect midrange performance, but not top end.