Q: Car idles; must be put in neutral at red lights. 1985 Pontiac Fiero

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I use my car for general driving, but it is not running very well. The other day I happened to meet a mechanic while I was in town and he, too, has a Fiero. He commented that the really nice thing about them is that they are easy to fix and repair. My car has an idling problem. If I do not put it into neutral at red lights and stop signs, it will die. When I'm driving on the interstate, it is difficult to control my car. It becomes very shaky when I reach 60 mph and then becomes very difficult to steer. The car acts like it has its own mind. It gives that feeling like there are a lot of loose screws that need tightening. In your experience, what is causing these problems?

Theses are probably two separate issues. The poor idle and stalling have numerous potential causes, but the first that come to mind is a vacuum leak. Vacuum leaks allow unmetered air to enter the engine, resulting in rough idle and/or stalling. One of the other things that comes to mind is a faulty idle air control valve (IAC).

As the name implies, the IAC is a stepper motor designed to regulate idle speed. A faulty IAC can result in an erratic idle and/or stalling. The shaking above 60 mph also has many possible causes. It could be something as simple as a bent rim or worn suspension part. The best advice I can give is to have the rough idling issue inspected by a trained technician, like one from YourMechanic.

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