Symptoms-
First start of the day, truck fires right up, and then I hear almost a metal to metal sound intermitant for about 10 seconds, then it completely goes away. It is coming from under the truck, right at the fuel pump. I assume it's the fuel pump, because there is nothing else around there, but what is the sound? Is the pump going out? It only does it first start, then it will not do it until the next day. If the pump is bad, how much is a new one?

 

Does it make the sound if you just turn the key on and not start the engine? If it's the pump, engine running or not will make no difference.
Does it sound like a mad bee? It's gulping large amounts of air and/or the pickup is clogged and there is a high vacuum between the pump and the tank.

 

Mad bee, exactly the sound. I wish I thought of that! Only does it after the engine is started. Key on pump running, no sound. Start truck and it does it. I had my wife start it with my head by the fuel pump and it is definatley coming from the pump. Time for a cleaning? or do you know how much a new pump is? thanks kwik

 

Sounds like air. Have you done the in tank and pre pump mods?

 

no, I have not done anything to the fuel line at all, completely stock.

 

Mine does that every now and then (rarely- only does it when cold). I turn the key on and while waiting for the light, I can hear it! Freaked me out at first, but I am not too worried yet.

 

Yeah, actually mine only does it when it is cold out, like below 40 for the night. If it is over that it does not make a sound, weird. I wonder if it is because the fuel is thicker? (I dont think it is, but I am guessing) I really need to do the pre-pump mods. I know I have a lot of air in there.

 

Mine does it at about the same. Dont think it has gotten that cold around here. After the first run, it wont do it again though.

 

Mine is the exact same. Maybe I wont worry too much yet, Thanks

 

I figure when its time to do something with the fuel pump, Ill just be forced to do what Kwik did.