Idling very high as well very erratic

 Buick Century

Idling very high as well very erratic

I am having a major issue with my 1996 Buick Century with 75k original miles and nobody seems to be able to figure out the problem. I replaced my fuel pump and I am in the process of replacing the radiator fan and motor. What I’m experiencing now is hesitation and acceleration coming from a complete stop. It feels almost as if there is some type of emission issue or a fuel issue. But it is idling very high as well very erratic if I put the air conditioner on too.  Has never lost power as of yet and check engine light is not on. I’ve had it hooked up to the computer and the mechanic said it’s not throwing any codes. He said that he hooked it up directly to the car and drove it and still no codes.

What could possibly be wrong with my car?

It seems to shift into first and second and third OK, nothing out of the ordinary. And sometimes the engine will rather but other than that I cannot come up with what is going on with this car. All my fluids are good. Transmission fluid good and color not gritty, doesn’t smell, oil’s good and doesn’t smell burnt. My temperature gauge has never raised to make me believe the engine is overheating but it’s just Driving really rough and feels as if it’s a gas issue or an emissions type of issue. Sometimes going from a stop it will hesitate like it doesn’t have enough gas to go. It’s almost like it feels from inside the car it feels like it’s falling apart. But on the outside of the car it doesn’t sound like it feels inside but it does idle loud. My car never idle that high before. It was not all that noise coming from under the hood I just know that I’m into this for $500 already and my car still not running properly just because it’s not throwing codes I don’t understand.

No codes is a good thing as it rules out most all sensors on the vehicle. However the I think I can help. The high idle is the big tip off for me. A higher than normal idle indicates a vacuum leak. A vacuum leak would cause everything you are experiencing and would NOT cause a code to be stored. The hesitation if from the engine sensors trying to compensate for the vacuum leak. The most common place for a vacuum leak on your specific engine would be the PCV valve hose.

How to locate a vacuum leak on an engine

Sometimes you are able to hear a slight whistle with the hood up and the engine running. Other times you may need to spray some non-flammable brake wash around suspected areas and listen for the engine rpms to change. Then dig deeper in the effected area of the engine.

Positive Crankcase Ventilation Valve Removal

pcv 1996 Buick Century diagram

  • Remove the vacuum hoses (1) from the fuel pressure regulator (3) and positive crankcase ventilation valve (2).
  • Remove the positive crankcase ventilation valve.