May be low on fluid or filter is clogged.
Need to confirm what model. The '92 should have the 4L60 (700r4) not the 4L60e. If it is the 4L60 it will have a T/V (Throttle Valve) cable leaving the passenger side of the pan running up to the throttle body, the cable will connect to the throttle linkage slightly above and outside of the throttle cable. If you have the newer electronic transmission there will be no cable and it will have a large wiring harness leaving the back drivers side of the tranny and either going to a stand alone TCU (Tranny control Module) on the drivers side inner fender or entering the firewall to the PCM in the cab. All the '92's that I have seen have the mechanical tranny. A WOT (Wide Open Throttle) shift can mean a few things. Does it skip a gear when it shifts or does it go from 1 to 2. If it shifts to 2nd at high RPM that would be the governor shifting the tranny meaning the valve body has issues. T/V cable issues do funky things, I would check that out first. Unlike the older Turbo 350/400 with the kick down the T/V in this tranny is more like a throttle position cable. It tells the tranny where the throttle is so the tranny can regulate line pressure (shift firmness) and shift timing. If the cable is broken the tranny thinks your at idle and will not shift the tranny until the internal governor overspeeds. Pull on the cable at the TB if it's broken or disconnected you should be able to tell, or you can clean out around the cable on the tranny and pull the bolt. Lift the cable mount out slowly if it is not damaged it should still be attached to the actuation lever in the tranny. If it skips 2 straight to drive the band is most likely damaged but this either happens slowly with progressively worse slipping to a failure or a loud bang and a broken band. Low fluid or clogged filter would usually cause low line pressure - weak shifts and slipping not WOT throttle shifts.
If you have the 4L60e all of the above is still applicable except for the T/V cable, the TCU/PCM sees the throttle from the TPS mounted to the throttle body and shifts the tranny electronically. If it is going from 1-2 with a governor shift you will need to check the 1-2 shift solenoid an the internal/external wiring issue. If it is skipping 2 as above.
An improperly assembled/tensioned T/V cable can cook a tranny as your line pressure will not match your throttle input. To adjust you need to hold the retainer on the clip and pull the ratcheting piece back away from the TB and release the tab. Push the gas pedal to the floor once and the cable tension will pull the adjuster back through the block to set it correctly. This will allow max line pressure at WOT.
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