Rough idle - white smelly exhaust

How does it idle in park , does it run ruff or smooth? Are any lights lit on the dash , check engine etc. ? Could have a partially plugged IAC air passage .idle air control (IAC) valve ! The engine computer uses the IAC to control idle , when under a load such as when put into gear the computer raises the idle ! It does this by allowing more air to by pass the closed throttle into the engine raising the idle ! If these air passages clog they restrict the air flow an cause a idle problem ! Now if it runs ruff at idle in park you could have vacuum leak ! Rough Idle How to Fix Ford Taurus Engine Stalls at Stop Signs

Possible Idle air control, simple to change on the throttle body

it's running rich. black smoke out tail pipe?

Check engine light on?

Two things come to mind.

1. Check transmission fluid, it may be low or need changing if it's brown and smells burnt
2. Bad Catalytic Converter; signs are a smelly, sulphur like exhaust, rough engine, excessive heat coming from under the car.

sounds like a fuel problem either a dirt blockage or the computor is mailfuctioning

More than likely you have an intake manufold leak! Replace gasket.

run the fault codes
indicates a cat converter problem coupled with injector problems

Not saying this for sure, but I had the same problem, and i have a 1994 xr7 V6 3.8 L , and all u need to do is set the idle down manually because your computer could have seen that the injector was stuck open, and tried to turn up idle to keep up with the amount of fuel being pumped, worth a shot :P

sounds like the EGR valve is sticky, take a small screw driver and tap the valve when the engine is at idle and you will notice a change in the way the engine runs, if the vehicle smooths out disconnect the valve and drive the vehicle and it should not cut off please let me know and dont forget to rate me!!

i think you should change the fuelfilter.