Should I keep my car or not?

I have a 2010 x5 45 is. She's a beauty,
and I would love to keep her. 204,000
miles at this point. The only issue is
that my engine light keeps coming on
when I accelerate (going up hill, and
getting on the highway). It misses. I've
been told it's due to needing new spark
plugs and coils, so of course, my
husband and his dad said they could
fix it. And, so they did.  All seemed well,
but it did it yet again. I really don't
want to get rid of it. HELP!