95 9C1 idle/shifting issue

I have a 1995 Caprice with LT1 (ex cop car) and in the last couple of months from time to time, while driving it will all of the sudden seem either like it has a slightly higher idle which I usually notice when stopped at a stop sign or something. Also this is when another issue seems to occur seeming like it is something transmission related. When I take off it usually shifts at 9 MPH but when this happens it seems it stays at 9 MPH and runs higher as I accelerate like maybe if the engine would be at 15 MPH and then take a hard shift. I have noticed though when this happens if I pull over and turn off the car for a few seconds, I can start it up and is fine until it decides to do it again which might not be for a couple weeks or a month or sometimes a short time later depending. Normally it happens during the day also of course most of when I drive is evening. I am thinking its not the transmission based on its not all the time. The transmission place took it for a ride right after it was doing it and it didnt do it for them after a pretty good ride. They said maybe a sensor. Anyone hear of such a thing or know anything about this. I use it as an emergency vehicle with the fire dept (Fire Police) and of course just want it to be reliable.

Thanks.

Welcome Aboard!

Any stored error codes for the transmission? Scanning for transmission codes will require a bi-directional scanner, such as a Tech-II or SnapOn MT-2500. It is possible that the trans temperature sensor or a trans pressure sensor (there are five) may be intermittent, forcing the trans into default mode (shifting at full line pressure).

Another possibility is an intermittent connection at the main trans harness (right rear corner of the trans). You can remove, clean, and inspect that without any major disassembly.

Hi. Thanks for the welcome. I wasnt real sure what kind of answer I would get as with a lot of things it can be muiltiple things it could be. Figured I would post and see what some opinions would be. They seem like good ones so far.

Thanks.