95 LX w/2.2 auto. I hope I can explain this without getting too wordy. Let's say I'm doing 70 down the highway running at exactly 2000 rpm. If I breath on the go pedal, it'll upshift like it's going into OD and drop to 1800 rpm, soon as I let off it drops out of "OD" and goes back up to 2000. I've checked fluid, it's fine. Tranny doesn't slip at all. 172,xxx miles on it. Only thing I've done is replaced the VSS when I first got it to fix the no cruise and blinking D4. I don't THINK it matters if it's cold or up to running temp but I have to admit I haven't paid attention, I just know it does it. TPS maybe?

 

At 70 mph, you are in 5th gear. It sounds like you are talking about the torque converter lockup.

Check for transmission codes, because there are some transmission codes that do not cause the D4 or S light to flash. I think some torque converter lockup codes are part of this group.

 

After checking for codes...if there are none.....inspect the throttle control cable to the trans (runs from the TB to the trans) and be sure that it is properly adjusted and moving as needed. If it is out of adjustment it can cause strange things with lock up and shifting.