Hydrocarbon is basically raw fuel, otherwise known as gasoline. The main reasons vehicles fail for high HC is defective spark delivery; in otherwords, a problem with the ignition or ignition timing system. However, we must first ensure your Nissan is in proper fuel control as well. Too much or not enough fuel will can cause high HC as well. These problems are refered to as Lean or Rich misfires. To avoid spending money on unneccessary repairs it's best to have a smog check repair station diagnose your Altima's smog check failure and repair only the smog components/systems which are defective.
posted by SmogTips Support
