I have a 93 montero 3.0. Got the dreaded SMOG requirement to register the truck. Got it done a year ago and it passed with flying colors so off I went. Not so fast the SMOG man said, "you failed your NO reading at 15 mph" Passing was 350, my reading was 700.

Went and dumped a can of guarentee pass into my tank and burned through a tank of premium, and put a 1/8 tank back in, checked tire pressure, and drove back in. not so fast the SMOG man said "it helped but you are still reading 500" Took the truck to a SMOG repair facitlity "You need a new O2 sensor, and new spark plug wires" After almost fainting when they said 600 bucks I did both my self. After replacing the O2 sensor and the wires, went back to see the SMOG man. Not so fast the SMOG man said "you are now reading 355" What!? passing is 350. So, I jumped in my Montero and drove around in 1st gear for about 15 min and pulled back into the SMOG mans office. With my poor Monty hotter than its been in awhile, "congradulations, you passed with a 349"
Man, I really hate California sometimes..........