i have an '01 5.4L 100K mi. ...... in park it idles fine, but when in drive and the brake on, it jumps back and forth from about 300rpm to 800rpm??? i know somethings wrong, but idk what..

 

Any CEL???Sounds like IAC valve is bad

 

sorry but i dont know much about vehicles....CEL?

 

Thats allright
Cheack engine light,service engine light or whatever you want to call it

 

ya the engine light came on and i took it to a shop...they said it was some kind of tube was broke.....they put a new one in, but it still does it...the engine light is off now though.

 

Well could you find out what tube it was they replaced and the code it had would be cool??
Since you have no codes i would disconnect both battery cables for 15-30 minutes.This will make the truck re-learn adaptive strategy when you hook the cables back up.

 

ya ill try sometime tomorrow or the next day to find out...thanks ill unhook the cables

 

when you re connect hook the positive terminal first,the red one

 

if theres one thing i do know its not to blow up the battery LOL thanks

 

hear is a video/sound clip of my engine....listen to the humming, what is that?

...nvm the sound quality makes it sound like a popping noise...but there is a quite loud humming noise when im idleing

 

I dunno all i hear is a wierd tapping noise with no sound of the motor in the background

you deleted it....
Try cleaning the IAC Valve and maybe buy a new PCV valve (PCV= $5-$10)
It sucks when there is no CEL!!!!!

 

ive already replaced the PCV after reading "Mason's Novel"... ...o yeh that tapping noise is coming from the motor also... but my phone couldnt pick up the humming as well..

 

That is a really loud tapping noise if that is coming from your truck.....Are you sure its not internal problems cause that sounded very loud...
cheack out fordmans thread