I have noticed my truck has picked up a surging for lack of a better word. Right around 1500rpm while in nuetral holding steady it is random meaning no set pattern. I do not notice it while in gear at all. Any ideas?

 

Mine does that at idle sometimes. If I stop at the bottom of the drive to get the mail, I can hear the rpms change...maybe by only 25-50, very subtle, but it's there. 8 times out of 10 it's rock solid. I get fuel in the same place all the time, FWIW. Maybe the spool valve that sets internal pressure is sticking?