Ford Repair: 2000 Mercury Sable, mercury sable, air jackets

Question
My car does not idle smoothly.  I have replaced trottle position sensor, both 02 sensors
and air idle control valve.  RMP is running about 500 when in gear and appears not
getting enough gas.  What now?


Answer
First I would like to apologize for not getting back to you sooner. I had some families issues that required attention and was away from my computer for a few days.I believe the problem is in the throttle body, where the IAC is bolted to. You get excessive carbon build up over time, and it needs to be cleaned. Disconnect the air filter duct work. Use a cleaner called air intake and throttle body cleaner available at most parts stores. This is basically carb. cleaner that is not as corrosive, so not to eat the protective coating inside the throttle body. Open the accelerator completely open and spray the cleaner inside the throttle body and clean it out with a cotton towel. Here is a quick explanation. At an idle, the valve inside the throttle body is closed shut. However, air still needs to pass through, enough for idle. There are air jackets that get clogged with carbon deposits that require regular cleaning. This carbon comes off from the engine blow-by. Also, replace the fuel filter if you have not already.