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1989 Ford F250 Pick Up - Has High hydrocarbons (HC). Why?

1989 ford F250 Pick Up pu 5.8L. Everything passes but the hydrocarbons are a little too high. What would cause them to be high? My truck won't pass because the hydrocarbons @15mph are 190, & for 25mph 192. what would cause that and what do I need to look at to fix it?? I cant afford a diagnostic.
Answer:

Usually high HC is caused by a defective engine ignition system. Out of the three systems your Ford's engine relies on to produce combustion (air intake, fuel delivery, and spark control), the spark system has the components which require replacement most often. Sparkplugs and spark wires are constantly exposed to high temperatures and high voltages. You must ensure your engine's ignition system is functioning properly, by inspecting all the sparkplugs and their wires. If any of the plugs look worn out or have excessive carbon build-up replace them immediately. You may use any brand of product designed to work in your vehicle. The distributor cap should also be inspected for cracks or excessive carbon deposits. If it appears that the cap may be faulty, you will need to replace it. More then likely you will see an instant performance increase once these corrections are made. There might also be a possibility that your Ford pickup's high HC problem is CO related. There is a condition called the "Rich Misfire" your Ford might be suffering from. This condition is created, when for any reason, the combustion chambers receive too much fuel, causing the fuel that is delivered to burn improperly and leave behind high levels of raw fuel(HC) and partially burned fuel(CO). Vehicles producing high HC for fuel management reasons usually begin producing normal HC levels once the fuel problems are corrected. However in this case if the smog test results showed normal CO emissions, then look closer at the engine ignition system. posted by SmogTips Support

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