i have a 94 buick skylark custom with obd 1.5,i found the test port but it only has three wires and has an obd 2 test port but obd 1.5 operating system.i tried autozone there test equipment won't read my system and i don't want to spend 200 bucks for a dedicated tester.the car runs fine except for the tranny not shifting but my check engine light comes on every now and then of course now my cruise control quite and so did my ac but the car was free with newer tires help. should i get a shop manual? can i download one for free?im not cheap just poor.

You gotta get those codes. Otherwise, you will be searching for days and no book will help.

Dealers can scan them for you, but you're gonna pay the min 1 hour shop labor time for them to scan it.