Very SLIGHT rattle on cold start

Yes so generally the not so violent type of shaking and carrying on looks to me on a car that I'm working on right now to be more like intermittent coil failures anything that will upset the balance of the 2Z Atkinson engine will cause the springs on the torque plate to compress to the point where they slammed together and then they slap back open and this happens very quickly clunk clunk clunk clunk when the fire is getting put out by the head gasket leaking It's more of an offset and power and the shaking is more violent is what it seems like in this particular car I'm working on right now that I have had for about 3 years I have not driven this car for quite a bit to keep the engine intact and not shake it apart I work on it every so often I change the EGR valve the other day and after putting in a new EGR valve and plugging it all up All this was done with the car completely disconnected from electrical power as soon as I put all the plugs back together on the car and went to start the car with everything correct The car started and ran. Pretty good actually and then started to make the rattling noise like we're discussing now and I also had 13 or 18 codes and most of these codes are related to coil circuit A and b through all four of them It's like 3154 or something I can't remember the codes but there's four separate ones and they're repeated some of them are stored One of them is permanent and then the whole series of four same codes again for this A and b ignition coil all four of them are repeated again as current and something to do with the EGR also I didn't write them all down but the EGR valve is brand new as in from Toyota the latest model. This was just done last evening so last night I ordered four new coils which these coils I have are only about 2 years old. So we'll see today if the coils make any difference I've written down all the codes and put them up I just wasn't going to write anything and put it here because it starts a pile of business that I don't have time to keep up with right now but look and see if there's any questions if you're running original coils at 160,000 mi take a look and see take a look at your EGR valve when it is closed Can you blow through it If so you may need to replace that EGR valve You can see pictures of leaking EGR valves right here on this site You can blow through them pour water through one in and watch it run out the other It looks like it should not The valve should be closed when you shut the car down or what have you is what it looks like to me I have not confirmed that by reading any technical material but every one of these I take off a car the valve looks closed if you take a pic and run it between the portion that the motor runs in and out to open the valve variably on a bad one you will see a space between so air can always flow from the EGR cooler to the engine I think that's bad on an idling engine that little flow of EGR could cause a stumble similar to putting the fire out with water except we're just putting it out with too much exhaust gas.

 

could be a very tiny hg leak, that's how they start.
have you cleaned the egr circuit?

 

Once these engines the 2Z start to take on any water you should be able to smell it on your dipstick just above the full dot it'll start creating a crust If you don't pull your stick out and wipe it all the time and you will smell it in your spark plug wells It is very prominent even when the leak is almost what will call miniscule.