| The EFI system sensors include a switch that tells the computer when you have the throttle floored. That caused a lot of fuel to be injected. Well if the computer senses that engine RPMs are low and the WOT switch says that you have the throttle floored, something is wrong. Both can't be right. You need to check the wiring going to the WOT switch (which is screwed to the side of the throttlebody) and, if the wiring is okay, use an ohmmeter to check the switch itself.
The code 21 is related to the emission control system and could also be the source of your car's troubles. Fuel vapors from the tank are routed to a chamber that contains activated charcoal. The charcoal traps and holds the vapors to prevent them from entering the atmosphere. (Prior to the introduction of this technology in 1971, about 20% of a car's total lifetime HC emissions came from raw fuel simply evaporating!) A hose connected to the engine allows the trapped vapors to be sucked into the engine during certain operating conditions.
A solenoid is used to prevent the vapors from entering the engine during idling. If the solenoid is bad engine idle can get screwy. |