at 148k miles, it has probably had a new chain by now. they tend to break about 125k. i would pull the valve covers and make sure it's NOT a chain making noise. wouldn't want it to break. means bent valves on the drivers side and lotsa money. without hearing the noise, i'd say the previous post is PROBABLY correct. whenever i see 1 of those engines for the first time, especially at or beyond 100k, i pull the covers and check for chain stretch. good luck, chuck.