RileyRice

So my truck only does this when it warms up. First thing in the morning or in the winter until it warms up it never does this.
When I drive it and stop it will go low in rpm’s and start shaking like it’s going to stall. I then can put it in neutral and step on the gas and idol it to 2000 rpm and it will stop. Lately that hasn’t been working every time. The longer I drive it the worse it gets until it gets cold again. It’s the 2009 Ford F150 with the 5.4 liter engine. I have had the cam phasers, timing chains, oil pump ( to high output oil pump), spark plugs, injectors and solenoids all changed about a year ago. The problem stopped for about 5 months and is back now again. I’ve heard things from it being ignition coils to a vacuum leak coming from the manifold. Anyone else have this problem and what was the fix? Thanks a ton!

Jimboy

You need to get your Diagnostic Trouble Codes (DTCs) read as a first step. Autozone and others do this for free. My first guess is a vacuum leak that may cause lean fuel mixture codes like a P174 (or similar). Get codes read and report back.

Michael Lindsey

I had this exact same problem with my Ford F-150 5.4 l it would run like crap after warmed up I found a split on the inside elbow vacuum line going to the crankcase ventilation. I replaced it and it has never run better