outlook.aj

I've noticed that when i say stop at a red light my 2008 4.0L V6 with automatic transmission seems to idle fine for about a minute or so and then it seems to vibrate or shake more than it was. Also while driving it seems to shake a little too especially now that the weather is getting warmer.

Any suggestions?

Nuke

Is your idle speed fluctuating?

I'd start with a good TB cleaning, fuel filter replacement and then run 1 or 2 tanks with SeaFoam just to rule out a dirt/buildup issue. Then begin with the more expensive troubleshooting if those don't work.

Alec

^^ agree. A clean TB did wonders for my rough idle

kevinmalec

Good suggestions above! Give it a try!

outlook.aj

This will probably sound silly but as I am so new to mustangs. What is the best way to clean the throttle body? Does it need to be removed or no?

Alec

Yes remove it and use a CRC throttle body cleaner. I spray it down and clean with a microfiber towel

Nuke

You can reuse the gasket, just don't be a gorilla when you remove the TB.

Alec

Yeah be careful not to spray any of the electrical connectors or be abrasive when cleaning

zanypunk

Depending on the miles. If it's a high mileage engine, I wouldn't reuse any gaskets. Why use a used gasket when it's not even expensive. :P
Gorilla

Alec

That's true. Now that I think about it, the 4.0 doesn't have a gasket for the TB, just an O-ring that's pre-installed in the TB and doesn't get removed