This is an Etec, right? If I had to guess, I'd suspect the TPS isn't sending the right data to the ECM so when the throttle plates open the injectors are not increasing fuel delivery so it bogs down.
But......rather than guess it's really best to connect up to a BRP scan system and look at the data.
In the absence of scanning the ECM, you use an ohm meter and back-probe the leads on the TPS. I don't know the resistance values you'll see, but you should see a static value with the throttle plates closed, then slowly open the plates until you get to wide open. On the meter you should see a smooth, constant change in resistance through the entire range of motion. If the values jump at any point then your issue is possibly the TPS.
Should be able to do this with the engine off an just probing the TPS directly.
KJ
