Engine Performance problem
1994 Toyota Tercel 4 cyl Front Wheel Drive Automatic 180000 miles
I have a vehicle I am working on for a friend. It is running very rich. Plugs are covered in soot and it blows a cloud of black smoke when throttled. I feel like it is choking itself of spraying way too much fuel. Plugs are never wet though. Exhaust is unobstructed. While running, I removed the tubing going to the PCV valve and the idle jumped dramatically. When I put it back on the vehicle stumbled and stalled. At Idle I can take the intake off, remove the PCV tube, cover the throttle body and the car will still run fine. It seems to have a misfire going on also, but that may just be a symptom of the rich condition. Any advice would be helpful. IAT sensor? Cool. Temp Sensor? O2 sensor?