Black soot in throttle body - 2005 Mercury Grand Marquis

you don't . check ISC located on throttle body

Check your throttle body for a restricted or dirty throttle plate. Remove the air horn attachment from air filter to the intake throttle body. Inside that intake is the moveable throttle plate. Use a warm lightly soapy wash cloth to clean throttle plate and area free from soot. Then assemble and recheck your problem. If still an isse you will need to disassemble the iac motor from intake manifold and clean inside that area with throttle body cleaner. Those methods are a must before diagnsing further.

Bad idle solenoid. Located on throttle body. It's black. Plugs in to wiring cable. You need a torx bit to remove. It's a cheap and easy fix. Also, get some throttle body cleaner and a tooth brush. Saturate the inside of the throttle body with cleaner and scrub out the black soot. Do this with throttle body in wide open position. Be sure to clean the edges of the butterfly good. They soot up and stick preventing throttle body from closing all the way.

Tbi cleaning alone won't fix it. The entire intake (big black plastic intake manifold) needs to be removed and cleaned. Also clean any soot on the head intake runners. And replace intake gasket. Be sure to remove all sensors from the intake before you clean it. Use rags that won't leave lint behind and intake cleaner.

This is an Idle Air Controll Circuit Fault code.

Take the IAC out of the car, plug it back in, turn the key on DO NOT START THE CAR WITH IT REMOVED.

You should see the IAC Pintle move a bit when you turn the key on.

Also, the needle, and seat inside the throttle body should be clean and not covered in soot. You should also clean the throttle body of any soot coking to maintain the desired Idle speed and functionality.

take a look at your throttle body. open it with the engine off and look for carbon (black soot) around the throttle plate. if present, clean it with carb or brake cleaner. if possible, remove it and clean it well

you need and alternator

when was the last time it was tuned up?
you need to check the air filter, and check the throttle body for black soot deposits.when you are pushing on the gas pedal you are giving the engine more air not fuel,your vehicle is fuel injected ,

could be exactly what u said.. a bad vacuum leak. spray a non flammable liquid in area of noise and see if u can cause an rpm change. suggest a throttle body/carb cleaner spray to perform test.

There is no idle adjustment screw. Idle is controlled by the ECM (Engine Control Module.) It controls what is called the IAC (Idle Air Control) motor, located in the throttle body. The throttle body and the IAC motor pintle have a tendancy to develop carbon deposits from the PCV system.

In order to fix your problem, you'll need to wipe the carbon deposits from the throttle body. First, purchase a can of throttle body/air intake cleaner from your local auto parts store. Remove the air intake boot from the throttle body, exposing the throttle blade inside. Open the throttle and spray it and the throttle blade down liberally with the cleaner. I like to let it soak for a little while, re-spray, then wipe it all clean with a rag. Repeat if necessary until it's clean and clear of deposits. If it has never been cleaned before, you'll notice a lot of black 'soot' deposits in there. When it's clean, you'll notice that the throttle blade most likely moves better, without sticking.

Re-install the air intake boot and start it up. It will be a little hard-starting at first, as the engine needs to **** in all the rest of that cleaner and burn it off. It'll only happen this one time and once it burns off, the engine should idle normally. If it still appears to be a low idle, you may need to consider taking a closer look at the IAC motor.

I hope this helps! :)