Can I have a felony and still be allowed to live in Costa Rica

It shouldn't cause a problem, but know there is no need to apply for a visa to enter the country, as your passport will suffice and you can stay for up to 90 days although that time period is not guaranteed. However, if you intend to apply for residency you may be required to list this with your other pertinent information.

Yes k. Is right. In practice 95 to 99% of the time you get a 90-day visa when you enter the country. Once in a blue moon somebody only gets 30 days, for no particular reason.

You will be required to present a police report with your application for residency and it will probably show up, unless you are living somewhere different from where the DWI happened, because the police report is done from where you currently live.  I just went through the  residency process.  I am not sure if you would be denied on the basis of something  from 10 years ago.  But, I did the 90 day thing for 13 years and most of the time didn't mind it.  A trip to Nicaragua or Panama is not a bad thing.  If you are in a hurry, you can go to the border, get your passport stamped, and return to Costa Rica the same day.  The 3 day requirement no longer exists.  I never got a 30 day limit, it was always 90 days.

If you wish to become a resident, the application requires a criminal background check.  It will show up.  If you purchase a home in Costa Rica for $200K or >, I am told by a CR lawyer that the felony will not then stop you from becoming a Citizen and resident.  If you have a passport, felony won't cause any issues.

fyi

Thank you for all answers and info! I am a very good person, hard working, raised three children, own my own home , etc. This felony DWI , on top of ALL the punishments that came with it, is trying to ruin my retired life. NOT fair! I have not once hurt another person nor have I been involved with drugs or gangs etc. I wish to live peacefully in a peaceful country with ample means to support myself and also to contribute to society and the country of Costa Rica.