Strange shifting on 95 auto

I'm not used to driving an auto but it seems like the shift points or the way the trany shifts is strange. Under light to moderate accel, it seems as though when you think the trany should shift it does not. A breif moment later, the revs increase slightly and the trany gets second with a decent surge that will sorta snap your neck back. I know this sounds strange but I have a 93 5-speed that I have driven for years. I know what moderate to full accel will do to your neck in these cars but I'm not in moderate to full accel with the auto.

Is there something wrong? Is there something I can check myself?

Is it possible that the previous owner did the J-mod to it?

Thomas

One other thing it might be is the early 4R70W's have a habit of the 1-2 accumulator springs and/or the accumulator itself breaking or going bad and causing a late or harsh 1-2 shift.
Part of the J-Mod is updating all of these accumulator pistons to the newer style. When I did the J-Mod to my 94 I noticed someone had already had replaced the 1-2 at one point so it had gone bad in less than 64k miles.
This is detailed in the article over at TCCOA. While you are at it you should look into doing all the upgrades listed there. You will only be out 140 bucks or so in parts and your trans will shift so much better.