too much fuel

[bluedemon]

anyone know anything about to much fuel intering the engine and how can i fix this problem?could it be a bad caty. any idea?i have a 4afe engine

[toyotaspeed90]

probably a bad (or going bad) oxygen sensor

[fredk]

too much fuel (rich) means too much fuel is being delivered in comparison to the air that the motor is pulling in, this results in pouring black smoke and running like crap. The ecu keeps this in check through the 02 sensor and the MAP sensor and the TPS sensor and coolant temp sensor as inputs, the output is controlled injector pulse width, or on time, what can get this messed up is several things, lo vacuum caused by a vacuum leak, a blocked up cat or a bad hose going to the map sensor, or a bad map, take the vacuum hose off the map at idle and it should pour black smoke and die out. Another easy test is there is an injector hi in the middle of the intake, it is controlled by a timer that may stick, after you get it warmed up, unplug it and see if it straightens up. Is your check engine lite on? The other sensors are a little harder to test, try the easy stuff first, and unplug the o2 and see if it trys to lean out in failsafe