Deep in debt from a loan shark, a young couple makes a DO or DIE decision to pay back a loan by smuggle drugs out of South America. While attempting an on the edge roller coaster ride back home to Los Angeles

Like others said - grammar & the seemingly incomplete second sentence was confusing to me.

Also, it's unclear what genre this is. So I don't know what I should expect from the movie. Is this something I would watch with my grandparents? My 5-year-old nephew? My date?
Based on this log line, I could imagine this being a comedy (roller coaster ride - not too gloomy and dark) or thriller (loan sharks chasing the couple) or drama (with lots of tears and revelations in the process of committing crime and recovering from debt.)

Maybe putting some kind of adjective in front of 'young couple' would help? i.e. A couple of ex-cons would probably react differently to the exact same situation compared to a couple of college professors (or a couple of cleaners, gardeners, funny, gloomy, violent, introverted, etc.) This might reveal the genre and imply what readers/viewers should expect.

I considered that:
In the year 2525, when Disney converts the little used Pan American rail line into the world's longest roller coaster, a desperately dumb couple uses their winning "First Rider-Front Car" ticket to smuggle drugs into LA. Interpol is in hot pursuit... in the end car.

Just when the think they have them with hands raised going down an incline they escape going up the next incline.

In the end it seemed too much like my NASCAR 3-D movie in Surround-o-Vision coming to a roller rink near you!

I like this a lot better than the other versions of the logline you've posted here - but the second sentence is totally unnecessary. Just stop at the full stop {period] and you have a decent log line.

As cynosurer says, "smuggling" - and they're in debt "to" a loan shark, not "from" one.