Toyota Repair: 1991 Toyota Check engine light, valve stem seals, piston rings

Question
I have a 1991 Toyota tierce with about 146,000 miles on it.The check engine light came on and I need to smog it. I have replaced the Catalytic Converter, O2 Sensor and soaked the EGR Valve due to it was clogged bad. It is also spewing Bluish smoke out of the pipe. Besides maybe having to replacing the EGR Valve any other suggestions on getting the check engine light off and stop the emissions?

Answer
EGR valves rarely go bad on toyotas, the most common problem in this case is that the egr passage in the intake manifold gets clogged up with carbon and becomes restricted, the passage needs to be checked and cleaned out, if the valve has also too much carbon it may need to be replaced but just replacing the valve may not solve the problem because of the above mentioned possibility. The blue smoke is another issue and if it only does this in the morning on start up the valve stem seals are probably leaking, if the smoke is there all the time it indicates worn piston rings. The check engine light can be turned off by either disconnecting the battery or pulling out the EFI fuse under the hood.