Toyota Repair: 93 Toyota V-6 P.U.

Question
I own a well maintained 93 Toyota Pick Up V-6 with 144k on it. After market cat 40k ago. I run mid grade gas. The truck passed emissions tests prior to 2013, no problem. Since then California changed the emissions standards. I have not re-placed any of the emissions parts since I have owned the truck except the cat at 105k.I pass 25mph test but fail 15 mph HC at 125 max is 92. Suggestions ? Thanks.

Answer
Hello
Higher than allowed HC levels are usually due to incomplete combustion to some degree, that is, too much unburned fuel is coming out of the exhaust, it's not that far over so maybe doing a tune up, new plugs ,wires etc and making sure the timing is correct at about 8 degrees advanced may help pass it. Also be sure the engine temperature goes up to normal when it's ready to be tested, put a can of gas treatment in the tank before testing it and drive it at higher speeds, freeway for about 20 minutes, autoparts stores have some additives that claim "guaranteed to pass" or your money back, give that a try, like I said it's not that far out of line, hope this helps.