Need help. My pruis runs great. Hit a giant hole 2 weeks ago. Had a bad rattle. Like a knock senor or heat shield. Raised car. Checked all for looseness. Nothing. 2 days later it went away. Came back today after 1 week. When I accelerate fast sound goes away. No codes. Could it be in the convertor. 220k new headgasket . Nothing looks loose.cannot find it at idle. Sounds like it could be in engine. Like valve train. But why would it go away. Thanks in advance.
