Does anyone know what this could be. There are 2 fuel pumps on the 2006 powerstroke right one frame mounted and the other underhood right. Well usually when the motor is cold i hear both running when truck is priming to start, and then once warm it just has the frame mounted one making noise when priming. But lately i havent heard the underhood one when its cold only sometimes. Then sometimes I hear it (underhood pump) when its idleing or when i come to a stop as it comes to an idle. i just changed the fuel filters to see if that would help but no, i have changed the filters at 9000 miles and now at 16,500. always motorcraft It seems to have a louder idle now but I guess its just because its about 10-15 degrees up here in the morning when I am leaving for work at 5:30am, or I am just hearing things. It still has the performance. i have a AFR stage 2 intake, Magnaflow dual no cat or muffler, and the accufab power elbow. No computer mods ever. And I always plug in when its that cold HELP

Also I remember it starting like a champ, it would crank and then come up quick in rpm to about 1000 then slowly fall back to idle, But now it cranks and slowly climbs up to idle but never above when starting. May sound wierd but it doesnt have that quick vroom sound when it initially starts, it more sluggish vrooooooom then its at idle.