I have a '06 (that's out of warranty) with the 5.4 and I've recently noticed a problem. When I'm off the gas and coasting around 30mph and then get back in half throttle the engine hesitates before it takes off, it doesn't do it at higher speeds just usually around 30mph. Against my better judgement I took it to the dealership today where I bought it for them to take a look at it. Well they were convinced it was a dirty throttle body, they cleaned it and I had them replace the fuel filter (they also cleaned the MAF sensor) and $230 later I still have the same problem. One other thing I thought was kinda odd, it that it's idling down around 500rpm, and I always thought it was around 700. I know I can take it back, but I don't have the money to throw $200-$300 at it everytime they attempt to fix it. The air filter is brand new as well. Any suggestions?

 

I to have a similar problem with mine its an 05 4.6l but mine starts with an engine miss fire at first 1000 rpm when cold and soon as it warms up its fine 80k miles i replaced the plugs and replace 1 coill ran good for a week and started acting up again I will try what your dealer did (cleaning the air intake sistem )and hope it will help. I also notice that the iddle surges periodicaly.

 

Any codes?

 

The scanned it and said there were no codes

 

i had the p0316 for a week or so an then po305 and thats when i thought it was the coil
i dont think its an injector because would it not do the same hot or cold .Fuel rail pressure is constante at 40 psi even on start up i think its more likely electrical because problem is intermitent but i could be wrong