My car is making a knocking sound when I drive over 5 mph. But when it's idling or I rev the engine it runs completely fine.....what would cause this?

something non-engine related. Trans or drivetrain. First check your lugs and make sure you don't have a wheel that is loose. And this is one of those super vague scenarios where you really need someone present to diagnose.

Ok thanks, I'll go check the lugs

any luck with this?

Yes sorry ment to post an update....a rock got into the drive shaft so every time it turned the rock would be making the noise.

nice. Glad you found it and glad you got to fix it, hopefully for free?

Yes the auto shop did it for free. Only had to pay 60 for a tow which isn't that bad. Thanks for your help and I know my lug nuts are tight now haha

I don't normally ask, but if you feel inclined to mark any of my responses helpful, it would really mean a lot to me (or best answer). I sincerely appreciate you coming back and letting me know / keeping in touch. A lot of folks don't, so it is nice. Also, I'm guessing they would have checked depending on the location of that rock and that it did no damage. But to make sure that if it was up against a seal, like the cv shaft seals that keep your trans fluid in the trans, that your seal is okay, etc. Or the boots that keep the cv shaft joints clean and lubricated. one on each end of each cv shaft, generally. Take care and feel free to PM me if you have additional questions in the future as I may not get a notification for it.