Hey guys I've swapped my old Chevrolet truck for a 2000 F150 4.6 that's been sitting in my grandfather's garage for about a year. It's a great truck and it runs nicely, except for one problem. If I first start it up and then drive to the end of my apartment complex and have to wait on traffic to clear, the truck starts to sound like it idles rougher, almost like something is loose under it and vibrating. And then, after a few minutes, the rpms start to drop for a second, and the engine sounds like it wants to die. then it just picks back up like normal. But it also s seems to make the vibrating sound if I'm sitting in traffic with my foot on the break for any long length of time. I thought since the brakes were involved it could be a vacuum leak, but it only seems to want to die if the engine hasn't been warmed up yet. For the life of me, I can't figure it out.

Anyone got any ideas? I love my new truck and after so many years of driving an old Chevrolet pickup I'm overjoyed to have something that isn't a POS.

thanks!

 

hhow many miles are on it? any service history? I would star off cleaning the throttle body(including the Idle Air Control). There is a nice how to in the tech articles section. See how it goes after. Might be time for a tune up. Spark plugs..

 

Congrats on your "new to you truck"
agrreed with jethat^^^ clean the throttle body and the IAC...& depending on miles and prior service...new plugs

it may have some sour gas too...if it had been sitting too long, think you mentioned "about a year".
some good fuel conditioner may help too, Techtron is widely accepted & found in Wally world.

concidering it has sat for some time...it maybe also a vacuum leak...check the PCV and asscoaited plumbing, especially the elbow on throttle body, ( known trouble spot)

 

fresh fuel, fuel filter and some fresh plugs won't hurt anything at all

 

Ok thanks guys I'll get right on that. I'll definitely check the PCV valve. didn't think that could be a problem on "newer" vehicles.

 

The valve and the vacuum line. The rubber elbow degrades when they get old so make sure your checking for leaks..

 

Well I checked the PCV eblow (after finally finding the thing. I'm still not used to how crammed and up under some things are in these newer models) and it looked fine. Think I might try some of that fuel conditioner.