Spark plug Blew out

Okay I Have a 98 Toyota Camry, Bought it as Is. Got
home and had a Crack at the Top of the Radiator,
okay that means im having to put water in it just
about every single day. Don’t run hot as long as I
keep an eye on the water level. I’ve been driving it
like that for about 3 months and a week ago the
second spark plugs and decided to shot out while I
had it in reverse. A friend says it only needs
tightening and it will run again just like that. And it
did. BUT it still runs with a little hesitation when I’m
idle. These “ABS” Light has been on but it came on
ONLY after we put a spare tire on. (mind you the
spare tire is still on so the "ABS" light itls
constantly on and off). I’ve been scared to run the
A/C but I have to keep making it to my job so I can
fix my ONLY way of transportation. If anyone has
any Opinions or Options on what I shouldn’t do or
what’s the first thing I should Do on getting this
fixed or Looked At. Do I just need new
Sparks/wires or is something stripped to make it
still hesitate a lil. Thanks.