I finally got around to dealing with the hard shifting of my automatic. There was a thread about this last year (don't know how to link, but it was thread id 36881), and a lot of people seemed interested/affected, but nobody ever posted a resolution.

Well, I took my '96 GXE to the dealer, and I showed him what I printed off the forum (Daniel Martin's summary was key). It turns out that the problem was a misadjusted throttle position sensor (which was the 1st item on DBM's list!). They fixed it, and now my car drives like it's brand-new! I can't believe I waited 9 months to do this, it just makes a world of difference.

Interestingly, this also seemed to fix the shift shock problem that I was having when the car was in overdrive (torque converter locked) and I let off the gas. There was another long thread about this last year (thread id 58044), and a misadjusted TPS was one of the possible causes listed on that thread as well. I haven't taken the car out on the highway since I got it fixed today, but some preliminary driving around town seems to indicate that the shift shock is gone or at least greatly diminished.

If your Maxima is having these problems, have it checked out! I know I'm glad I did. Also, the dealer replaced all the O2 sensors as part of an old recall that had never been performed (I bought the car used last year), and I always love to get something for nothing.

BTW, I only went to the dealer because the first mechanic I took it to said that the shifting felt "fine" to him (he must be on crack), and coincidentally he didn't have any of the equipment to check my list anyway.