Nissan Repair: Smog, fresh oil, fuel treatment

Question
I HAVE AN 88 PATHFINDER WITH 149,000 MILES AND A V6. THE SMOG IS DUE NEXT MONTH AND THE LAST TIME IT WAS SMOGGED IT JUST BEARLY PASS THE HC AT 15 MPH AND THE 25 MPH TEST FOR HC WAS CLOSE TO MAX. ALSO. THE CO WAS ABOVE AVERAGE BUT BELOW MAX. AT BOTH SPEEDS. THE NOX WAS EXCELLENT, BELOW AVERAGE. WHAT CAN I DO TO LOWER THE HC READING BEFORE I GO TO HAVE IT SMOG NEXT MONTH, SO IT WILL HAVE A GOOD CHANCE OF PASSING? I CHECK THE ENGINE TIMING AND IT'S GOOD.

Answer
Hal,

First, do a tuneup.  That is, change the plugs, wires, cap and rotor.  Also, do a fresh oil change and change the air filter and the fuel filter.  Then get a tank of premium and purchase a bottle of CD2 fuel treatment and then go drive the car until it is hot (operating temperature) with the air on.  A warm engine swells up the rings and helps pass the test.  You should be fine with the aforementioned being done.