So like the title says, my car vibrates really bad when I am sitting at a light or idling. It seems to reduce the vibration if I shift to Neutral. I have a 94 3.4L V6. Also a side note: I have replaced my spark plugs, the whole transmission, and brakes. I have had my car inspected by the brake shop and they said everything looks fine and they dont what could cause the vibration. It gets worse when I have the heat or air on.

 

double triple check the spark plug wires to make sure there going to the right plugs.

 

Some kind of vaccum leak somewhere?

 

check battery and terminal connections, friend had a similar problem on an accord, hope it help

 

what kind of transmission does it have and what was replaced?

 

Okay I checked the spark plug wires, everything is going to the right place. The battery connection is perfect. As for the transmission, it is an automatic. They replaced all the electronics inside the transmission (solenoids and stuff).

 

have you checked all the mounts and motor mounts? is anything touching underneith?

 

is the car running crapy at a idle. can u tell were the vibration is coming from. might try cleaning the iac valve.

 

i dont know if this will help or not but at idle i had a problem with my car vibrating pretty bad dash vibrated and could feel it threw out the car and would go away right off of idle i think it was the timing chain that fixed that on mine. now i just have a vibration at higher rpm

 

My Z28 was doing the exact same thing. I replaced spark plugs, optispark and the cat and it solved it.

But generally my car is -although not as much as its been before- a big mobile vibrator, even in N.