Does anyone know who can reprogram the computer to raise the idle speed? My truck idles rough at 550 rpm but smooths out at 600. 01 F150 4.6

 

It doesn't need a reprogram(a re-boot maybe or KAM reset) - You prolly need to clean your throttle body, IAC and MAF sensors . Change your PCV valve and scope out yor vac lines for leaks.

 

You have a problem to find.
It should idle at about 670 +/- fully warmed.
The IAC is the first place to check out. Is the connector in place? Is it stuck closed or limited in operation? etc.
Take the connector off while the engine is running fully warmed. If the idle does not drop much,, it's not working correctly.
Don't change the idle stop.

 

The truck has had the "rough idle problem " since new, so I thought I could I might get around it by reprogramming the computer to set the base idle up from 550 to 600 without the a/c on.

 

my 05 4.6 does the same, 550 when warm, and rough

 

I did the same as Jbrew. Worked on almost every recent model Ford I've had. 99 Taurus V6, 97 F150 5.4, 99 F150 5.4, 95 Tbird 4.6, and will probably work on my 06 F150 when it develops that problem. I also use a K&N filter which may contribute to some of the "fouling" of the sensors due to the oil in them.

 

Blu man, Reprogramming can be done but it may still not make the operation work as it should.
The PCM is already programmed for the normal idle about 650 +/- the same as all other trucks.
If your seeing a problem then then there is a fault present in the idle system.
Here is how it is supposed to work.
At cold start, the PCM opens the IAC for extra air and higher idle speeds.
The ECT , IAT signals the PCM the engine will be a cold start. This causes the injectors to add a lot of fuel and raise the idle RPM into the 1200 rpm range +/-, then slowly comes down as the engine heats up and the OX sensors take over fuel control.
The 500 rpm you see is the throttle stop setting open just enough to keep the engine running and the throttle plate from sticking closed when the engine cools down.
In addition this throttle stop setting has to be below the IAC normal IDLE rpm so the IAC has an automatic airflow adjustment range, otherwise the idle speed goes too high to long..
The PCM programmed idle speed is 'CHASED AFTER" by the PCM program and sensor inputs until a very close match is obtained between the program value and the actual running idle speed.
If anyone has any different operation, you have a problem.
This is the same operation since the first EFI in 1985 and accross all the control systems on all models with full EFI.
The IAC has to be checked for gum, sticky or no operation etc.
The TB has to be clean.

 

HI!... My BBK 75MM TB on my 5.4 has a adjustment screw which could be used to adjust the idle mechanically. I believe the stock one has it too. You could try that for the extra 50 - 100 RPM you want.

 

Don't play with the hard stop on the throttle body.

If you're idling too low (which you are, a bit), you've got other problems that need to be checked and addressed, such as the IAC like others have mentioned.