Idle Problems

[2twenty5]

My Mustang is an '05 V6 completely stock and has been having idle problems recently. When this problem occurs, the idle drops down to 500 RPM and fights to stay running. Usually this happens as I am slowing down at an intersection or coming to a stop, however it is not a consistent problem and seems to happen only once to twice a week. If it dies, it still fights to stay running when I restart, usually causing me to give it some gas to keep it running if I'm at a stop light. I have also noticed that if it can keep running and I put the accelerator down while driving and gun it for a few seconds that it will idle normally the next time I come to a stop.

I have searched forums and found posts by other owners who have had similar problems, but have yet to find anyone who has found a solution to the problem. I know about the TSB about fuel pump problems, but I this seems to be different issue. If anyone has any information or advice it would be greatly appreciated.

 

[2twenty5]

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[rygenstormlocke]

Try this, its in the owners manual....


Because your vehicle’s engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. To begin this process:
1. With the vehicle at a complete stop, set the parking brake.
2. Put the gearshift in P (Park) (automatic transmission) or the neutral
position (manual transmission), turn off all accessories and start the
engine.
3. Run the engine until it reaches normal operating temperature.
4. Allow the engine to idle for at least one minute.
5. Turn the A/C on and allow the engine to idle for at least one minute.
6. Drive the vehicle to complete the relearning process.
• The vehicle may need to be driven 10 miles (16 km) or more to
relearn the idle and fuel trim strategy.
• If you do not allow the engine to relearn its idle trim, the idle
quality of your vehicle may be adversely affected until the idle
trim is eventually relearned.
When the battery is disconnected or a new battery installed, the
transmission must relearn its adaptive strategy. As a result of this, the
transmission may shift firmly. This operation is considered normal and
Maintenance and Specifications
205
will not affect function or durability of the transmission. Over time the
adaptive learning process will fully update transmission operation to its
optimum shift feel."