I read DougH's recent threads with passing concern until I failed my inspection yesterday for high NOx. I have now read and reread everything. And this is the course of action that I going to take.

Optmize cooling system by:
1. New radiator
2. Install missing fan shourd
3. Run straight water for the test, add antifreeze later

Optmize fuel delivery system by:
1. Run a can of BG 44K throught before test
2. New fuel filter
3. Premimum gas with a octane booster
4. Reconnect bypass butterflies for the test

And a new catalytic converter

All this needs to done to the Montero anyway, but it stinks to have to it for the state. I am also thinking about O2 sensor, temperture sensor, and going to a shop for the timing if I don't pass this time. Is there anything that I might be missing? <img src="/forums/images/graemlins/confused.gif" alt="" />

Your SR is equipt with an EGR valve- be absolutely sure the EGR is fully operational. It should be enough to almost stall the engine when the ERG pintle is opened manually. If not, clean out the EGR valve pintle and the EGR passages in the intake.

Joel, CA

I high Octane gas burns slower, that's why it's used in high compression engines to prevent detnonation and ping. The lower octane stuff burns better on older trucks.
Nobody belives me. <img src="/forums/images/graemlins/sleeping.gif" alt="" />

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