One problem related to emission control has been reported for the 1999 Ford Mustang. The most recently reported issues are listed below.
Check engine light stays on constantly. Engines idles rough and stales at about 1500 rpm's. If you turn on the heater or ac. The problem gets worse. I scanned the car and got a misfire code and an egr code. Replaced all ignition parts and all emission parts and the code and problem won't go away. Help please. Any info can be sent to skippema@yahoo. Com thanks.