Just to get to tuning. After a regular tuneup, you'll need to set timing and AFR to help with HCs.
Below are common failures which are likely to produce high Hydrocarbon HC. Hydrocarbons are basically raw fuel, otherwise known as Gasoline. High Hydrocarbon (HC) emissions are almost always a sign of poor fuel ignition. However, it's not always that the engine's ignition system is responsible...
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Other stuff to help reduce NOx. IMO the hardest to pass, especially if you don't have a 3-way Cat.
Nitrogen Oxide or NO is created when an engine's combustion chamber temperature reaches over 2500F. Vehicle manufacturers have designed several systems, which when working properly, lower nitric oxide emissions. Below are common failures which may cause your car, truck, van, suv, or motorhome to...
www.smogtips.com
Check your Charcoal Canister system and gas cap for leaks - part of the test is to pressurize the fuel system to look for leaks.
YMMV