I have a 2004 super crew cab with 5.4 triton. When engine is warm, it will stall at traffic lights or stop signs. The tach will rev up and down and then stall. I replaced the MAF and put a new gasket on the air filter tray. The check engine light is on. Took it to the Ford garage and they said it would be 2200.00 dollars and they still wouldn't guarantee that would work. Does anyone have any suggestions. My next thing would be the vapor management valve and then the intake manifold. When traveling on the road it runs great.

 

That makes no sense at all...spend $2200 and not fix anything ??

 

I have a 04 super crew with the 5.4 as well and it's doing the same thing. My CEL is on and is showing codes p0351 p0356 and p1000. I replaced the plugs and packs on cylinders 1 and 2. Then replaced the fuel filter and ran some seafoam through it still nothing. It runs great going down the road but soon as I stop at a light it will drop below 500 rpms and bounce back up while in drive.

 

Mine is showing codes P0171 and P0174. I just tried the seafoam tonight. Hopefully that will help.

 

I took my truck to another mechanic and in about an hour he had figured out what was wrong and two hours later it was done. It was a vac hose on the back side of the intake. He had to take the air cleaner, throttle body and the intake off in order to reach the hose. Just wanted to let everyone know that this is a common problem with this model of Ford.

 

Vac hose or plenum O ring is a common problem.