I recently put a new 4.9 in my truck, it uses electric fuel injection. I have the harness wired how it was before I pulled the motor, but I have one extra plug and I can't seem to find where it goes.

 

That is the AC Compressor harness plug.

Also, pull the Orange Fram filter off and replace with Motorcraft FL-1A filter.

That's known as the "Orange Can of Death".

 

There was an article years ago in the (US News and World Report), magazine which I don't know if it is still in print or not, but at any rate, for consumer testing they had cut a Fram filter in half and found that it only contained an old used Fish container with Chinese writing on it. That was back in the late 70's! Definitely get a FL-1A

 

Thanks for the info, I just needed a cheepy filter for the first start up as for the AC, this truck didn't come with AC so I guess I'll tuck the wire out of the way.