PLEASE HELP 06 4.0 shutter and ruff idle

[Bad06stang]

Hey guys I posted this topic on mustang forums but no body responded to my post. I have an 06 4.0 V6 automatic, totally stock but with dual GT take offs. The car has 79K miles, is extremely well maintained, and not beaten on to often. I am having an issue with my car stumbling during idle and have to be what sounds like backfire pops coming from the exhaust. Whenever you are sitting at a light with the car in drive, it will stumble and go from the normal 750 RPMs to about 500 RPMs then catch itself and go to normal. Then 5 seconds later it will do the same thing, and this process repeats over and over again every few seconds and feels like the car is going to stall. If you stand behind the car you can hear the car is running like shit. Its burbling and popping and sounds erratic. When you rev the car up and hold the revs at about 2 grand the car stumbles and shakes and the exhaust pops. The thing is It drives with no issues, at least that I can hear on the freeway and all. No loss of power, no nothing. The service engine soon light has never come on once, which I find weird. I just changed the oil last week with fully synth 5-30, ran some gum out injector cleaner through a tank of gas, and the car started doing this about a day after I did that service. Today I installed a new fuel filter, and filled up the tank with 87 octane from another gas station in case I got some bad gas. Nothing has changed at all. Right now I have the battery disconnected to see if it clears the issue but I highly doubt it will do anything. Does anybody have any ideas what the hell I can try to fix this car? The throttle body is spotless, I cleaned the maf not too long ago, about 25K on the spark plugs. What is wrong?

Here is a video I made of the car and how shitty it runs, I have a friend idling it at 2K. You can hear the burbles I am taking about and all.

http://youtu.be/rELhQ1UWvcs

I am a broke college student and I would rather not have to take it to the stealership.. Thanks guys

 

[86GT351]

You say the maintenance is up to date. Have you checked/changed your spark plugs? Pull one out and inspect it. Could very possibly be bad.

 

[Clipboard]

You say the maintenance is up to date. Have you checked/changed your spark plugs? Pull one out and inspect it. Could very possibly be bad.

ya sounds like a sparkplug issue

 

[TexasBlownV8]

1. spark plugs. 2. ignition wires 3. fuel filter 4. coil pack

My stock spark plugs on the driver side were shot after about 25k miles.

 

[Bad06stang]

Thank you for the help guys! I went out and pulled the passenger side middle plug this morning and it looks bad. I was looking in my haynes manual at pictures of spark plugs and what they mean, and to me it looks like the picture that says its too hot. Does it look that way to you guys? Anyways I am going to go ahead and replace the plugs with a set of Motorcrafts, I don't know why I put in Bosch the last time.

 

[Bad06stang]

Well I don't know what did it but the car is running awesomely. The other day I drove it about 50 miles across town non stop on the freeway, I got off and the car ran great. Before this I put in a new fuel filter, but that didnt solve the problem right away and I doubt it has anything to do with it. I bought a set of motorcraft plugs to put in, so I did that today. (It is such an easy job on the 4.0 it took me no more than 25 mins.) Every single one of the plugs had the burn marks on them like above. (anyone no what that indicates? I have never seen it before.) The car runs perfectly smooth as silk and the problem is gone. Thanks for the help guys!