Q: 1999 Dodge Durango

Hello, There are a number of things that may cause a rough idle. A rough idle may be caused by things such as low fuel pressure, low voltage to the fuel injectors, dirty fuel injectors, a vacuum leak, a faulty Oxygen sensor, dirty or failing idle air control valve, a faulty camshaft or crankshaft sensor, faulty spark plugs or wires ad many other things. Any of these possibilities may relate to fuel or spark problems that will disrupt the normal combustion process that would otherwise allow the motor to run smoothly.

Another common issue that may cause this to happen is a dirty or faulty mass air flow sensor. The mass air flow sensor monitors air intake as it is mixed with fuel prior to being injected into the motor. This sensor relays vital information to the ECM which uses this to make adjustments to fuel supply to the motor. A dirty or faulty sensor can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bit of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.