If you have your cdl and drive a truck told company I have two DUI 1991 and 1994 they don't even show up on my back ground check. But I also have one in 1988 if I was to go into canada would this show up and what would be done

They might not show because a regular background check done by a company may not have full access to your records. Yes, Immigration Canada will be able to see it, in fact they have this exact question on the Canadian Immigration website.

You must apply for deemed re-habilitation since the crime was 10 or more years ago, please check the link below. Basically your applying for a "pardon" of sorts or more to have the Canadian government let you in despite the conviction.

CIC Canada | Overcoming criminal inadmissibility (http://www.cic.gc.ca/english/visit/conviction.asp#deemed)