I really don't mean to be annoying or troll just I know this is the best place for knowledge.. I fixed my misfire but, as I was all happy I passed someone and my engine light came on... Driving to work today I slowed, then rolled a stop and got back on the gas and nothing happened then BAM it just slammed into gear, I pulled over thinking it popped a line because its done that before... Anyway nothing leaking, and it has the correct amount of fluid..
At work (Autozone) I jacked a scanner and pulled 4 Codes! Two were for the O2 Sensor (P0140,P1133), and the Other two were for the Transmission IMS (P1825,P1826) I can't imagine they're not related... I'm hoping the O2 caused the engine to run crappy and while shifting causing the PCM to read the Transmission Code, Plausible?
I'm just getting sick of this, It was a beast and ran beautiful... Oh well, I had a warranty on the O2 so I picked up a new one, will install and report. Why would I need a new O2 sensor when this one is 2 months old? Why would my Transmission act up? arghhh... 3800sc 4T65-HD

------------------
86 Fiero GTX project now tearing up the street, My build thread! 3800sc, interior, wheels, suspension and more! https://www.fiero.nl/forum/Forum1/HTML/089483.html

Start looking for PCM ground problems. There should be a trans to engine bolt where grounds bolt to a stud on the bolt. Even if the plastic shielding on the wires look good the copper inside can be broken. If you pull on the wires and they stretch, the copper is broken inside. Also, with the engine running, wiggle harness around different areas. If you notice a stumble, you found a harness problem. Hmmm, cold wheather, salt, snow, corrosion at the bolt?
Transmission solenoids, O2 sensors and Ignition module rely heavily on good grounds. That is why there is more than one in the PCM harness.

There is a common problem with those tranny's with the PCS going bad, when that happens it will do exactly what you mentioned and will get worse after it's hot. Hopefully your problem is something else, I have successfully replaced the PCS on my grand prix and been fine for over 30k miles now, but the success rate on tranny lasting after that is low.

------------------
86 Fiero GT 4spd - (pending L67 swap)
98 GTP - Some mods