Hello,

I noticed a difference between normal weather and cold wet weather in performance, engine hesitate while acceleration, I was thinking could it be a defective vapor purge valve?!
A hesitation comes when cold wet weather.
thanks
​​​​​​​Ford Excursion 5.4L

 

Why would you jump to that conclusion?

There's nothing in the evidence you've provided that would suggest such a fault. If there was an electrical or functional fault in that valve, the OBDII system should detect it and post a fault code.

 

Check to see if any water is dripping in onto the COPS or plugs from the rear of the hood seal. The way the seal fits on some of these trucks water can come in at the center section of the seal by the cowl and get the COPS wet which can cause wet weather misfires.

 

Might be! Im gonna check this out..thank you

 

Project SH, the code I pick p0453 related to evaporative system..what do you recommend?!

 

I'd recommend you disclose the full scope of all observations so that time isn't wasted next time.

I'd also recommend you completely identify what you're driving in your post so we don't have to waste even more time asking for such pertinent details, like what year.

A P0453 has nothing to do with the purge valve, it instead indicates an issue with the signal from the fuel tank pressure sensor.