Help! 2004 F-150 5.4L stalling and missing at idle
#1
Help! 2004 F-150 5.4L stalling and missing at idle
Well I recently (as in 2 days ago) bought a 2004 Ford F-150 FX-4 with the 5.4L 3 valve v8. I drove it back to my house which was close to a 5 hour drive without much of an issue. Well, now today I stopped at a intersection and the truck completely died. After a few cranks the engine fired right up. But now at idle it acts like it wants to stall and runs rough until you give it gas. If you raise the rpms just a little bit the engine runs smooth. There are absolutely no engine lights so I am kind of lost. i was really looking forward to enjoying my new truck this weekend, but sounds like I might spend it under the hood. I did some research but sounds like people with similar problems have engine codes. PLEASE HELP!! Thanks.
#2
Senior Member
Sounds like a vacuum leak, which from multiple posts here, is a problem with the 5.4 - specifically at the rear of the throttle body, where the hose going to the PCV Valve (on the valve cover), at the bend collapses and winds up with a small hole. Enough for the engine to struggle at idle, but masks the condition when you give it more gas. Search on vacuum leak on this forum (and in the 1997-2003 section) where this comes up over and over.
#3
Senior Member
Since you have a newer truck than mine ('98), you also have "Coil On Plugs." If one is bad, you may get the same symptoms, where at higher engine RPM, the engine seems to compensate well - but not at idle. Just saw that with my stepson's 2006 Crown Victoria. Got a code reader, showing Cylinder 3 misfire. Got one off a wreck to test the theory, and that fixed it! Go to an auto parts store, and let them check it. If the coil is bad, it'll show up immediately.
#5
Here is an update to my original post. After cleaning then installing a new throttle body, left side cam phaser, and a new fuel filter finally found the problem. It was the fuel control module. The damn thing broke in half when I removed it. I had no engine lights except one time which came back left bank cam phaser. Just wanted to update in case someone else has a similar issue.