Spark plug question (97 4.6 T-Bird)

Thanks, I'll file these suggestions. Wait...., could you elaborate on the thermostat please. I replaced it when I upgraded the intake and its whatever over the counter temp range they sell at Auto Zone.

NOX goes up with combustion chamber and intake charge temperature - and combustion chamber and intake charge temperatures go up if a hotter thermostat is installed. You may getter better fuel mileage with a hotter 'stat, but it is possible to cause a vehicle to fail NOX by simply installing too hot a thermostat. Yours is not nearly close enough to the limit to be put over by the thermostat, but it is possible dropping the operating temp MAY lower your NOX a measurable amount. When vehicles are on the dyno for E-Test in warm weather, if the operator fails to run the big cooling fans, a perfectly calibrated car can fail dismally on NOX - and pass 10 minutes later after the fans are turned on and pointed at the front of the car.

The car passed. What are you doing to this poor guy?

LOL, yeah..., I already think too much.

Just answering his question, and hopefully educating a few people on the list about NOX emissions issues.

Mission accomplished and appreciated. We gave our 93 Isuzu Rodeo to our daughter and I always get a call at smog time so I filed it away.

This group has been a lifesaver for me. The only time this car was ever at the dealer was on the intake manifold warranty and the replacement was as bad as the original. (my only real complaint about the car)

When I had to /finally/ unload the factory intake and was kinda (very) nervous someone not only directed me to a good source for a new one but e-mailed me a set of step by step photos of when they had done it. Of the automotive n/g's this one seems to be the best when it comes to getting help.