I have a 03 tl with 120k bought it in March have done 2 oil changes and a tranny flush. I bought it with 116895 miles when do you think i should change the plugs? and what else should i do to keep it running?

 

Timing belt? Biggest concern.

I would take out ONE spark plug, and check the condition and brand. That will tell you if it has been replaced. If they are not NGK plugs, then change them to NGK Iridiums. If they are OEM, then change them as well.

OEM is some type of NGK too, but they should be visibly worn out by now.