I have a 2003 Dodge Neon that is making a horrible grinding/vibrating noise when accelerating and it seems to be more on the passenger side. The problem is worse when cold and tends to lessen as the car warms up for a bit after driving. Sometimes when cold as I sit at a stop light the car starts vibrating pretty loud, if i put the car into neurtal it stops. When driving if I let off the gas the car stops vibrating also. I have had the local mechanic replace the control arms and ball joints, passenger side engine mount and put a couple of bolts in the exhaust manifold. Struts have been checked also and seem to be fine. Im at a loss..Please help..thanks.

 

When I hear the word grinding I think of wheel bearings. Try lifting the wheel and spinning it. is it noisy? Also, rock the wheel up and down then left and right. Check for play in the hub.

 

Having same problem did u come across a fix, I've replaced the upper motor mount, wheel bearing, both outer tie rod ends, even went as far as removing splash guard.

 

in my case thought that too replaced passenger side. Thought about driver side but I know vibration travels but not like that and the "swerve" test didnt show any results.