Toyota Repair: Toyota smokes, valve stem seals, 1989 toyota tercel

Question
Hi: I have a 1989 Toyota Tercel with a 1.5 engine and a manual transmission. There is 129,000 miles on the car. The timinig belt went out a few months ago while I was driving on the road. I replaced the timing belt. Now when I start the car it smokes a lot from the tail pipe. If I let the car idle it continues to smoke. However, if I take the car for a ride it smokes for a short time and then stops. When I restart the car during the course of the day it does not smoke. When the car sits overnight in my garage and I start it that's when there is a lot of smoke. Do you know what is causing this and what needs to be done to fix it?
Thanks for your help.
Al

Answer
The most common cause for this is that the valve stem seals are leaking, they can be replaced without removing the cylinder head but it's still pretty expensive because there is a lot of labor time involved, expect to spend around $900 for this repair.