96 Ford Windstar Running Lean

[4ogre]

I have a 96 Ford Windstar 3.8 with 99,000 miles with engine light on. Took to mechanic which it showed P0171/174 error. He replaced all O2 sensors. Light is still on with same codes so my husband changed EGR valve. Light is still on and van idles very rough and stalls out if you stop for too long. Also very strong smell coming from exhaust. I have to get my E-Check in October to renew my tags but I know it will fail. Any help would be greatly appreciated!

[KPVSR]

Sounds similar to another post a day or two ago. Try cleaning or replacing the idle air controller.

[4ogre]

Originally Posted by KPVSR

Sounds similar to another post a day or two ago. Try cleaning or replacing the idle air controller.

I thought I read that those codes mean different things for the older Windstars.?

[SonOfDolomite]

I had the same codes coming up on my 95. I just cleaned off the MAF sensor and it went away, it also really helped on the rough idle.

[ModMech]

www.crownvic.net/tech/cleanmaf.html or www.lincolnsonline.com

[Chicin]

I know your throtle body may have a notice that says not to clean it,but you may want to give it a try if the other suggesstions don't work. Spray throtle body cleaner inside and carefully wipe it out with an old rag (clean).Of course you must disconnect the air filter and rubber boot first.I have a 96 and it works for me.

[winterover]

I had the exact same problem...spent 200 bucks on O2 sensors and still had the CEL on... turned out that I had a vacuum leak! The guy at Autozone helped me find it and I finally fixed it with a 2 dollar hose! So....check all the hoses coming off the upper air intake and also the hoses at the front of the engine (pass side) and also the back towards the firewall. My leak turned out to be the on right on top of the intake (the big main one)... Good luck....

[ModMech]

DO NOT clean the throttle body! It WILL NOT, in fact cannot affect lean or rich, so it cannot help.

[cdestes]

i had the same problem with my 1996 windstar. I also found a vaccuum leak after about $200 in parts it was the line leaving the pvc valve on the back of the motor close to the fire wall. Check all lines good for any leaks before spending a boat load of money on unneeded parts (like i did)

[DRW1000]

171/174 codes indicate a lean condition on the left and right banks. This can be caused by an intake leak or if the MAF is giving inaccurate readings. In both instances the PCM does not know the correct amount of air entering the intake system and cannot accurately inject the correct amount of fuel.

I agree with Mod Mech in that the throttle body is most likely not the cause.

Cleaning the MAF may be a good start as is checking all of your hoses for cracks and ensure that they are tightly connected at both ends.

[wiswind]

To clean your MAF (Mass Airflow Sensor)....Use a non-residue electronic cleaner. The MAF is located in between the air filter and the flexible hose going to the throttle body. Is like 1/2 of the big barrel that the air cleaner is in.

Also, The windstar is very prone to vacuum leaks. Check the PCV hose that connects to the top of the Upper intake manifold....right next to the throttle body and IAC. Mine developed a crack on the inside of the elbow.... Also follow the hose to the back valve cover....and verify that it has not come loose from the PCV valve. There are a bunch of vacuum connectors on the back of the upper intake manifold.....If you have done any repair activity in the engine compartment.....think over where your hands were.....and check to see if you may have bumped any vacuum hose loose (I know it sounds stupid....but I have done it a few times).

There are 3 vacuum actuated items on top of the lower intake manifold...on the passenger side. The vacuum hoses are red....and look like a heavy gauge electrical wire. The items are the Intake Manifold Runner Controls (IMRC) and the fuel pressure regulator. If one of those was off...you should get another code....but could be leaking.

Also, check to see if your heater works...and if you can turn the selector and get no airflow from the fan (that is the selection at the 12:00 position on the AC / Heat / Vent selector. If one of those things does not work......Well....the heater blend door (controlled from the temperature adjust selector) and the airflow ON / OFF are vacuum controlled..........a couple more little hoses that could have come loose.

Then....look for things that cost money....unless someone else can add to the "free and likely" list.