Although it is symptomatic of a plugged cat, IMO it wouldn't plug suddenly from what was done.

How old is the wire harness? Was the throttle actuator unplugged for any reason? IIRC, someone please jump in that knows for certain...those models had both an electronic throttle actuator that would reach full open throttle and a cable that only opened the throttle about 1/3rd of the way. I'm thinking it may only be opening part throttle mechanically due to a disconnected, defective or bad wire harness at the throttle actuator.

Good luck!!!

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