Mazda Protege shakes during drive

I don’t know exactly the right word to use but my protege knocks (?) while I’m driving. I had recently put in new alternator and power steering belts so I thought those might be loose and they were a little. I fixed those and it still does it. I’m thinking it’s a fuel filter or spark plugs. While I’m driving it rocks back/forward every so often and I got the check engine light for a while. Any ideas? Thanks.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code not just their translation into English and post it back here.

could be a spun or bad bearing

Need a better description of the knock(?). Does it sound like a screwdriver tapping on a vavle cover, or a hammer tapping on an engine block? Loose belts and clogged filters don’t normally cause tapping or knocking sounds.

SORRY, MY BAD!!! How do these old posts get bumped up to the top?