Shake and whine.

If you're at a stop with the car in park and step on the brake will the rpms go up and down like when coming to a stop?Also have you checked for codes in the computer yet?

Have you ever replaced the coolant temp sensor?Bad ones can cause idle issues a lot of other symptoms.

Was the connector to it corroded?Also have you checked for vacuum leaks damaged loose vacuum lines etc?

I may just add my 2 bobs worth in here, I have been browsing this thread and I am wondering if it is in fact a vacuum related issue, is there any correlation between the vibration and breaking? If so you may have a minor booster leak causing an issue.

OK, another option may be that the engine is in tension, try backing off all the mounts and driving around the block, re tighten mounts this may settle the engine into position and re tighten all mounts, just need to start eliminating some basics.

Another trick is a mount rebalance there is even a Saturn bulletin for this. Loosen all the mounts and the three exhaust nuts on the down pipe off the exhaust manifold. Plus the two exhaust 10mm bolts below the oil pan and the three 13mm nuts at the back of the cat. Then rock the engine with enthusiasm the tight the exhaust nuts at the exhaust manifold then the back of the cat and the two 10mm bolts by the oil pan. Then tighten the mount bolts.

Thanks you for using 2Carpros, and tell a friend!