Engine vibration at idle

[JME5150]

Hey All,
I am hoping someone can point me in the right direction. I have 2004 V6 4.0 L
When the explorer is at idle, there is a slight vibration thru the vehicle. The engine all the way to the tail pipe is vibrating. The vibrations get worse when the compressor is running...(a/c or defroster).There is no check engine light, I don't know if it is a rough idle because the engine does sound smooth and there is no fluctuation on the tach.
I did change the plugs but not the plug wires, I changed the fuel filter, had the injectors cleaned, cleaned the MAF and the throttle body and changed the air filter. i have not done anything to egr valve, and I dont think this year explorer has an IAC. I also put in STP gas treatment and injector cleaner. Nothing so far seems to work. Am I dealing with a vacume leak or maybe a broken motor mount? I would really appreciate some input and opinions.
Thanks in advance
JME5150

 

[NHale623]

Vacuum leaks typically do not cause vibration or rough running issues. If you had a leak that large, your CEL would be lit.

Might be a motor mount, but I seriously doubt it.

Start with the simple items first, did you check the plug wires when you changed the plugs? PCV?

How many miles are on the truck?

 

[JME5150]

Vacuum leaks typically do not cause vibration or rough running issues. If you had a leak that large, your CEL would be lit.

Might be a motor mount, but I seriously doubt it.

Start with the simple items first, did you check the plug wires when you changed the plugs? PCV?

How many miles are on the truck?

No I didn't check the PCV Valve, or the wires yet. On this year engine, is the PCV located on top or is it behind the engine by the firewall? The truck just clocked 50,000 miles.

 

[aldive]

Rough idling is rather common in the V6.

Take a look at http://www.explorerforum.com/forums/showthread.php?t=169335&highlight=idle

 

[NHale623]

I don't know where your PCV is located. Odds are, it's behind the engine in the worst possible location. When you changed your plugs, what did the old plugs look like? What brand did you install? Why did you change the plugs, was it because of the vibration?

Check the wires. Try running the engine at night while looking under the hood. Try misting the wires with water while you look. If there's a bad wire, you'll see it.

Just got 50,000 miles on it? That isn't much, do you do alot of driving around town? Do you have access to a scanner?