89 Camry failed emissions for the 1st time ever

[toyota_camry_89]

Hi everyone,

I have an 89 4cyl LE 3SFE Camry that has about 180,000 miles on it. It's always passed emissions tests with readings well within limits. Now for the 1st time it failed the Nitrogen oxide test (and almost failed Hydrocarbons also). Here's the readings:

HydroCarbs: standard=1.4 GPM, 2009_reading=1.3245 GPM, 2007_reading=0.1516 GPM

CO: standard=30.0 GPM, 2009_reading=7.85, 2007_reading=2.5982

NOx: standard=2.5 GPM, 2009_reading=5.5984, 2007_reading=0.4706

As you can see, the current 2009 readings are way out of line compared with 2007, and all the previous test history going back 10 years also.

Based on those numbers, anybody have any obvious thoughts as to what might be the problem? I was thinking start with testing of the O2 sensor and EGR valve. If something is glaringly wrong, I will fix/clean/replace it and get the free emissions re-test. Catalytic converter is probably beyond my ability and that's where I would take it to the shop.

Just to note, the engine check light is *not* on, I have noticed no problems with the performance of the engine. It's got new spark plugs I put in about 2 months ago. Catalytic converter, O2 sensor, and EGR valve are all original. One thing is the ignition coil fried a few months ago -- I replaced it and the spark plugs since figuring they may have been fouled. Don't know if that could have affected other things besides spark plugs?

Thanks in advance,

Bryan