Hey guys, I've done a lot of reading in here, but this is my first post. I have a 2004 5.4 F150, and as of last week, it idles horribly and then usually won't stay running. If I'm on the gas, driving, it's fine. As soon as I come to a stop, it wants to quit on me. Upon reading some other posts regarding similar problems, I thought it may have been a dirty throttle body. I pulled that off, cleaned it good, and the truck still runs bad.

I took it in yesterday and hooked it up to a computer and it threw out codes for bad o2 sensors. Upon reading other posts on here, I've learned that despite the o2 sensor codes, that may not be the actual problem.

One cause (that I've read over and over on these posts) is possibly the vacuum line on the back of the intake. I tried looking for it, to see if it is still connected, but I have no clue how/where to find it. Any help would be greatly appreciated!!!!!

Thanks guys!!

 

Post all DTC's.

 

I do not have them, but if I hook it back up, I'll be sure to post them.

 

When pushing the gas do you smell any kind of odor? Also do you hear any kind of noise? Did it show any misfire codes?

 

I had that problem... That hose is under plastic cover over engine and between firewall and top of engine.. I had a hole in it... Fixed it $30 part at Ford. Never had issue again. I have a 2003 f150 4*4 v8 4.6