How to pull codes

I have searched this and there is no direct answer. Either the search feature is terrible or when I type "how to check engine codes", I must not be typing it in properly . I understand you can have a AP or go to Atozone and have them pull it but can you do it yourself through the car. In my 90/91 you can check the codes through the car it self by connecting certain connectors together and doing the shifter dance.

Problem:
Have driven the car around 1000 miles since I purchased it 2 weeks ago and was driving with cruise control and it sputtered went off cruise, then CEL and Cruise flashing came on. I have looked and seen various codes but need to confirm for the obvious reason.
Car is possible stage 2 and does need a tune, probably the reason for this. Also have done oil change with filter, tranny and rear diff fluid change. Only use BP and Shell premium gas. Car still averages 25 MPG highway .

Thanks in advance and hope everyone is having a great Thanksgiving.

How can a car be possibly stage 2? If the car still drives, why don't you just take it to autozone? Otherwise, I believe you can do it by turning the car off and on several times or with a paper clip by connected to pins of the obd port.

take it to advance and have them pull the code. done... and make sure its tuned or your screwed, otherwise well see another new thread.

turn it back to stock if you don't have any money to tune it.

pull the fuse panel cover off, fish around until your find the test connector. plug it in and it will show the codes on the dash.

If I don't have any money to tune it I don't have any money to turn it back to stock either haha. So I guess you can't pull the codes yourself or you guys aren't sure how to do it?
I was told I may possibly have "sounds like, Stage 2", from someone on here. Regardless if it is 1, 2 or stock I need to get the code pulled and then figure out what it is. Is there a list of what eah code is?

Mods:
AEM CAI
Full exhaust system, headers, up/dp, turbo back exhaust
that's as far as I am aware of

see my post above, then search for vacation pix on this forum.