Spark knock or exhaust leak?
My car makes a rattle sound when accelerating but
I already tried higher octane gas and changed egr
valve. When I turn it on I here like a doing going
from the manifolds. But it does t last long. What
could it be?
If the higher octane hasn't helped, it could be an exhaust shield around the catalytic convertor that has rusted loose and rattling. You can clamp it down, tack weld it back in place or remove it. Don't let a muffler shop sell you a new convertor if that is the issue.
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