Intermittently I have a screaching noise when driving. Just when I think it won't stop it does. Happens whether the engine is cold or hot. Usually when shifiting gears.
Fan Belt noise? on 1991 Mercury Capri
Either one or more of your belts is worn and probably loose and you will need a shop to replace one or more to eliminate the noise also they can check your power steering pump alternator etc at the same time. You can get a estimate for belt replacement here https://repairpal.com/estimator?car_type_id=5847 and locate a shop near you here https://repairpal.com/directory?address=89110&car_brand_names=Mercury
could be your aftermarket belt doesnt quite have the same groves as the original....it'll wear down or just get one from Napa