I have a 2000 Grand Marquis Ls. I am having a problem in the winter. Mostly whenever the temp is under 45degrees. The problem is my car humms through the throttle body. Its off and on, short and long humms. It usually went away when I step on the gas and it came back whenever. It went away when the car warmed up. It also had a very rough idle. I thought it might be the IAC.
To my findings the rough idle came from the IAC. But about an hour and a half later I started the car up cold to go home after scool and the car starts to humm and doesnt stop now. Im lost. I was told to replace the pcv valve.

Where is the pcv valve on a 2000 and how do you take it out to check it?

 

Larry, Did you find your PCV Valve ? It should be located in the center of the passenger side valve cover. The PCV valve is a simple ball type check valve, make sure when you shake it you can hear the ball move back and forth, if not clean with some carb cleaner or replace it. You should be able to blow through it in one direction but not the other.

 

I am having the same problem with my 2000 Marquis, now that winter is here and the temp is colder.

Who told you to replace the PCV valve, and was that the solution to the humming noise?

 

Hey searchlight4759 and farmermark. Sorry it took so long to reply. School is kickin my butt. Yes I found it. Thanks. It wasnt that. I found that the IAC tube was the problem. I replaced it with an older model Cougars IAC tube with a muffler. I used the the soft rubber elbow from the old 1 to stick it on there. Its ugly and not a prefect fit but its been a week and a half, and I havent heard the noise once. Just incase it turns out to be something else.

Thanks again. Im finding more problems as I go but, it I will be good.

 

it helps me a lot thanks for the post.

 

What is an IAC valve, and where is it located