okay guys i have a 90 crx si. recently it started making a weird grinding sound while im driving. it doesnt grind when i change into any of the gears. but as soon as i step on the gas it starts making that sound. its off and on. usually you can hear it more when im just cruising it, but usually when i WOT you cant hear it at all. car has 226,000 miles on it. but i've never had any problems before. it was just out of know where. does anybody think they know what it could be??