I have a 90 Chevy Lumina Euro 3.1 and I was wondering how to do the paper clip trick to get the computer to spit out codes to see what is wrong with my car, overheating and loss of power at times then step on gas and it goes good. Do I even have a computer in the car to do that with?
If your MIL (aka check engine light) is not on, there probably won't be anything there to help you.
Hoever, if it is. Short terminal 'A' and 'B', ingition "on" engine not running, check engine light flashes, code 12 to start, three times (flash, short pause, two flash, long pause, repeat twice), then the stored codes start.
Google is yor friend, search this group.