Rough idle after replacing alternator (??)

[Mammoth]

So I change my alternator and now I'm getting a rough idle. I heard that you have to give the ECU module time to reset it's self after disconnecting the battery and once it does it'll straighten out. Any truth to this? If not any suggestions?

 

[BAD RONALD]

Check your owner's manual. I do remember reading somewhere when I did a battery change years ago that there is a recalibration after a disconnect that takes place during a short period of driving time.

I also recall some advice about putting the truck in Drive and WITH YOUR LEFT FOOT FIRMLY ON THE BRAKE PEDAL accelerating to 2500 rpm for a few seconds to accomplish the same adaptation. I leave it to the board to debunk this idea.

 

[Mammoth]

Thanks Bad Ronald. I dunno, is it safe taking advice from someone called "Bad Ronald" lol! Anyways I'll try the 2500 RPM thing in a bit. I changed the Alternator Monday so it's been driven briefly since then, just maybe not enough.

 

[Bedrck47]

I would suggest that you get the codes read and if P1000 comes up then you haven't completed the drive cycle test if anything else comes up then let us know.

 

[Mammoth]

I'm sorry if this is a stupid question but where do I get the codes read.

 

[BAD RONALD]

Auto Zone will do it for no charge.

You can buy your own scanner and do it yourself if you prefer.

Code Reader - CAN OBDII Multilingual Code Reader

 

[Mammoth]

Thanks BadRonald!

 

[Mammoth]

I will get the codes check and post my findings Bedrck47

 

[Bedrck47]

Take a can of carb cleaner and spray around the vacuum hoses to see if you have and leaks spray around the rear of the throttle body. If you have any vacuum leaks you will know by an increase in rpm's

 

[Mammoth]

Ok so earlier while it was idling I checked all the vaccum lines nothing seemed to be an issue there but I noticed the interior lights were kind of dimming in and out. I bought a refurbished alternator that came out of a 2004 expedition with a 4.6, could that be an issue considering I have a 00' with a 5.4?