Re: 97 Mustang Cold Start Problem
If your check engine light is not on, it may be that the Idle Air Control Valve (IAC) is bad. IAC's usually cause a hard start, or stalling condition. When starting the engine and at idle, the throttle plate is closed and the only air entering the engine is through the IAC. This is all controlled by the Powertrain Contol Module. It uses the IAC to allow a small amount of air to enter the engine for starting and to adjust idle speed. The IAC is mounted to the upper intake manifold with two small bolts, and has a small electrical connector on it. It is about two by four inches. It may be sticking when cold, you can remove it (be careful, it may have a paper gasket) and clean it out with an Air Intake Cleaner. If this doesn't help, it may have failed and need replacing.