Goddamn thing.
It has always done this(since I bought it brand new), so I know its not dead or dying.

Mash the gas off the line, and it shifts to second at about 3750rpm. Keep it floored, it hits second at about the same rpm.

I adjusted the TV cable doing what the tech articles say. Push the button down, push that stop thing all the way back, release the button, then turn the throttle to WOT.

The first time I did it, I turned the throttle linkage by hand. Second time I did it, I got in the car and pushed the pedal to the floor.

After the first time, I noticed the car shifted to 2nd gear (under normal accel) at a higher rpm/speed than before. The WOT upshifts were a little bit higher.. a tad over 4000rpm.

After I adjusted it the second time(pushing the pedal)... it was shifting exactly how it was before I adjusted it the first time. Yippee...

I was thinking about the Q-jet. I remember reading a while back, that there are some things in the way of the throttle blade that prevent the secondaries from opening completely. Perhaps since technically, the engine never is going to WOT (at least with the stock q-jet) no matter how hard I hit the pedal, its always going to shift early. That makes sense to me... doesn't mean I like it though..

So what do you guys think?

(This is a '89 L98 with a stock Q-jet and Performer intake. So its not even getting near the top of the power band the way its shifting.)

 

I would try readjusting it one more time. Have someone sit in the car and push the gas to the floor while you adjust it, about 1cm of slack is alowable. If this doesent fix the problem you might have a sticking governer.
Good Luck!
SSC

 

To adjust the TV Cable skip the book method and do this: Press the D button on the adjuster and loosen the cable setting. Now, have someone floor the gas pedal while you check to see if the throttle plate is open all the way. Usually they are off a little and will wiggle. Do whatever you have to do to get it open solid. Now, with the pedal floored, press the D button and pull the cable back as hard as you can and release the button. You now have the engine, tranny and gas pedal all in sync at WOT. Mark the cable so if for some reason it gets moved you can know where to put it again. The problem with the 'self adjust method' is that it bends things and puts them permanently out of whack. It is also the full TV setting, which is theoretically what the GM method does.