Tylus

I'm new to the 4.6, not V8's. That being said, my Stang has an abnormally rough idle when not in gear. During the warm-up phase, the car runs great and hasa nice smooth idle. You can barely tell the motor is running. Once she is fully warm-up though, the motor runs like it is severely leaned out or maybe missing on 1 or 2 cylinders.

Is this normal? My 5.4 in my truck runs smooth as silk, and I've heard in the truck forums that they're 4.6's run rough in the trucks.

Thanks

35thGT_Mustang

My car used to idle extremely smooth, but i just changed the intake manifold and now it idles pretty rough. I wouldn't say that you are missing. i have heard that most of the 4.6's idle rough.

BleedinBlue

My car doesn't idle extremely smooth...not real rough, but not real smooth. Its hard to tell about yours really, it depends on how bad the idle is...

Make sense?

klfutrelle

Maybe you put some bad gas in it.

Tylus

I'm fairly sure it isn't bad gas. The idle is almost like when you put a decent cam into a motor. I don't have the lope of a big cam, but I've definately got the shaking. I may have to get a tuner and see if that fixes the issue.

BleedinBlue

Vacuum leak maybe?

Sap

I was going to say bad o2 sensor, but you'd notice that thoughout the powerband too. Just not during warm up. When you say rough idle, do you notice any jumps or lags in RPM's or just notice the motor shakes quite a bit, the motor in my 03 shakes pretty decently so I would say that is normal.

E.

immencedata

mine does that to i replaced the IAC the PVC TPS no vacum leaks cleaned throttle body still does it i took it to a ford dealer and te reading came back IAC so i put a new one on and it still does it