I bought my cl recently with 154,000 mi on it. I don't know if the timing belt was just changed or is due for what I would imagine be the second or even third change. How would I tell if one is needed?

 

any service records? Have a acura dealer check their computer for records. If no records, then have a shop check the belt. The timing belt should be changed every 105k so this is either going to be the first change (badly needed) or you dont need to chage it for another 50k.