My 88 4Runner failed the NOX too. The truck had been sitting for about 2 weeks prior to me driving to the testing station which was only about 3 minutes away. The testing people told me to drive it around for about an hour. I drove a half hour up the highway, turned around, drove back to the testing station. I then passed the test. You should try the same thing.

88 4R, 350 V8, R150 5 speed Sold <...uot; />
97 4R, stock, daily driver
98 Sienna, kid and dog hauler, wife's ride