I too have a '90 LSI and love it.
You can search all of my posts to see all of the troubles I have had lately but don't let that discourage you!
The PO (previous owner) play havac on the girl. Looks like the coolant sensor went bad and instead of tracking down the actual problem, he/she/it decided to rip out most of the wires that control the engine

Other little issues came up but with the help of this forum and especially Jerry, everything is running just fine.
Fun little car to have. We go 4-wheeling alot in it.
Wish I could help you with your identification though.
I'm sure Jerry or someone else can get it for you.
Good luck and again Welcome to the Forums.