Toyota Repair: Emissions Testing...., 1988 toyota camry, combustion temperatures

Question
Hello Ted,

I recently began working on my 1988 Toyota Camry LE Sedan to take for it annual emissions testing. I have replaced the plugs, fuel filter, air filter, and plug wires.

My car failed the emissions testing on the NOx ppm portion. The allowable reading is 1258, but my cars reading was 1601.

What should I check and/or replace to correct this problem, so I can get my car passed the emissions testing her in Georgia?

Thanks for your time and advice.

Regards,
C. Craven


Answer
High NOx readings are usually caused by either high combustion temperatures or an EGR(exhaust gas recirculation) system malfunction, have the egr system checked to see if it is working properly, make sure the  engine is not overheating,have the engine ignition timing checked.