2004 Ford Explorer 6 cyl Four Wheel Drive Automatic 81000 miles
I have a 2004 Ford Explorer. My alternator went bad and so I had to replace it. I went to the auto parts store and they needed the manufacturer date because the computer had different part numbers based on manufacturer dates. Mine had a production date of 12/15/2003. The one they gave me (I did not know at the time) was the one for manufacture date of 11/2003 or earlier. I put it in and my car started acting funny at start up. The rpms would drop to about 500 and raise up to 1000 and then sometimes when the rpms would drop down at start up, the truck would die. Once it got running, there was no problem. It was not showing a code or anything. I was not having this problem before I put in the alternator. Do you know if Ford made different alternators for the Explorer? Also, if I put the worng one in do you think it might give me this problem? Any help would be great.
Did your battery drain out
then the idle memory was lost you need to drive it for a good 100 or so miles before it relearn the idle
also I would check for a vacuum leak
check around the intake manifold