Hey Scotty! I have a 2005 toyota matrix(150 000 km) base model, automatic that have a really bad vibration at idle. it doesn't matter if it is on drive, park or neutral. the vibration disappear as soon i go higher than 1000rpm. If you look at the engine when it's idling, you can clearly see it shaking.
i have already done a few thing to resolve the problem including: cleaning the electronic throttle body, replacing air filter, spark plugs, ignition coils, all motor mounts(including the transmission one) checking for vacuum leaks(no leaks), checking intake manifold gasket( new), checking for compression issue( perfect compression)**.**
I was about to change the upstream o2 sensor because my scanner can't read it but i thought Hey! why not ask Scotty for an honest answer and since you have a matrix yourself, you might know if it is a common problem.
Thank's for your help!