Q: 01 mustang v6 running rough at idle and drive. Please help. Replaced a bunch, still can't figure out issue.

asked by on June 04, 2017

my 2001 3.8 mustang runs rough. Sometimes it runs rough at idle, if it's not running rough at idle it will run rough when put into drive. There is a lack of power and sputtering with a miss when driven, most of the time. It was throwing a code for miss in cylinder 2. I changed the injector and it seemed to run somewhat better but a day later it feels to run the same as before. I have put all new plugs, wires, and a coil pack in. Put a new fuel filter and air filter in. Cleaned the MAF. Not sure what the issue is at all. Please help.

My car has 115000 miles.
My car has an automatic transmission.

This may be a sign of a faulty MAP sensor as the vehicle responds adversely to a load put on the motor (i.e. putting it in gear, turning on AC or engaging the brakes). The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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