Hey I have a 2000 expedition that is giving me the SES light and running very ruff. I did the OBII and gave me back the o2 sensor #2 lean. Does any body know which sensor this is and it's location. I would also note that around 65 mpg the light starts to blink on & off and gets pretty ruff. Will the replacement of the 02 sensor fix this problem. Thanks

 

I have wasted money trying to fix my idle problem from the process of elimination. Now, I'm going to tell you what to do my friend to eliminate your idle problem. Go and buy you some throttle body cleaner and a new IAC idle air control, read up on some posted threads about cleaning the throttle body, some have pics. disassemble your throttle body and clean it real good. replace the iac. put it back together, and your expedition will run like new. I have a 2000 EB 4X4. Do this and your rough ride will be gone.

 

After reading many of the post, I decided to tear down the throtle body assembly, but just before I started removing it, after disconnecting all the sensors, I started to remove the PCV Valve Hose.........Woooooo! Hold your horses, the 3 inch hose that connects to the PCV Valve which Ford has taken so much care to cover it with foam rubber, had a big hole in it. I replaced the hose cost $1.00 re connected everthing and presto. Runs like a charm after 206,600 miles. Dealer wanted $280. for a Mass Air Flow Sensor, $110./hour for labor, and an extra 150. for hooking it up to the diagnostic machine. Talk about getting ripped off. Do yourself a favor, check all those vacuum hoses, clean the throtle body, which I will tear down this w/e just to ensure the passages that cannot be seen are not restricted, and forget the dealer unless is something that you really can't fix. My thanks to the guy who posted about the carbon clogged passages.

 

The oxygen sensors are located in the exhaust pipe that attaches to the exhaust headers. If you don't have a lift , and are handy, remove the fender skirt from the fender carefully, you can then see them real well and have good access to them. Bank 1 is where piston #1 is, Bank 2 is the opposite side. Depending on how you are looking at the truck, normally it would be looking at the truck from the front.

 

Could be a missfire thats causing the o2 problem. I would get the obII read again and see if a missfire is being reported.