2000 Taurus dies at idle after warmed up

[Breeves002]

You have many conflicting statements. Earlier it was going into closed loop and running lean due to what we would think is a vacuum leak.

You said two PCV hoses, isn't there only one? Are you checking the correct lines?

Does your code reader read pending codes? It's possible that the open loop issue just started happening and hasn't set a code yet.

[routerman]

Well I can't find anywhere it mentions pending codes. Just refers to DTC's. It's dual overhead cam and has a PCV on each cover with a hose coming up to the accordian style hose that's running up to the TB from the air filter assembly. I assume those are the PCV valves similar to what use to connect to the air filter assemblies back in the day when working on a car was quite simple but I could be showing my age...lol

[behlinla]

This is what you're looking for under the throttle body. The pliers are pointing to a large crack that was leaking:

[routerman]

ok, I'd been referring to the littler lines on top of the valve covers and when you said under I found it and the elbow is collapsed. Thanks for the picture as well. Now all I have to do is figure out how to get to that freakin clamp to pull it off and assume I should get the whole assembly like you show since chances are the other end is shot too.

[behlinla]

Just FYI, the lines you were referring to are called crankcase breather tubes. They replace the air that is sucked out through the PCV. Also, the part that is bad is referred to as the PCV elbow. The actual PCV valve is at the base of the tube and is stuck into the engine.

This will tell you how to replace the PCV valve and the PCV elbow: The 10 Min Duratec Pcv Replacment Thread

[routerman]

I replaced the elbow since Auto Zone had one and that's fixed the check engine light. Still has a slight erratic idle where it will drop down to 500 RPM but recovers and not stalling anymore so I assume I have another vacuum leak and will look at the PCV valve end this weekend. Thanks for the help and behlinla for the clarification on the ccbt's.

[Breeves002]

I guessed he was looking at the breather lines. I made the same mistake when I first came to this forum too and you guys were trying to help me with the same codes! I didn't actually say that because I was in a hurry to type it lol.

Behlinla, we should write a guide on the P0171 and P0174 codes lol! Same with EGR codes. So many threads on them. They wouldn't take nearly as long to write as that misfire guide either.

My guess is the computer was still in open loop when the data was read, maybe it just hadn't fallen into closed loop quite yet. Or something was messed up.

Did you replace your IAC? Can fix that erratic idle. Do a cigar smoke test to find more leaks.

[behlinla]

Originally Posted by Breeves002

My guess is the computer was still in open loop when the data was read, maybe it just hadn't fallen into closed loop quite yet. Or something was messed up.

It could be if he just started the car a few seconds before the data capture. But the coolant temp is 197º so if the car was running for more than 20-30 seconds it should be in closed loop.


routerman, could you do another data capture with the car warmed up and idling for us? Make sure the car has been idling a minute or two before starting the capture. You could just leave the car running when you get home and do it before you normally shut it off. That will tell us if you have any more vacuum leaks or if it's just a bad IAC.

[e_town]

Long time reader, great community here that has helped tons w/ my wifes 2000 Duratech. I've been battling this same issue for a year on and off.

I have a scan tool and i've learned a bunch about the O2 sensor and fuel trims from reading information found on this forum and many links to external info sources.

My wifes car starts fine, never had an issues there. Had a pretty bad leak around the injector seal in the past that was troubleshooted via propane / starting fluid. Sprayed around the engine until idle changed. Was throwing vac leak code and running poorly with the 71 / 74 lean as well. That fixed it a little, then replaced the PCV boot. Didn't do much at all.

So, still have lean on bank 1 and 2 codes, but no vac leak codes. My scan tool (ELM bluetooth w/ Torque app for Android) can graph live for O2 values, and they work once warmed. LTFT is way high, 25 or so which leads me to believe this has been going on for a while. The app that connects to the scan tool also shows fuel system status; whether or not it's in open or closed loop.

Under load (acceleration) the car seems just fine. It's at idle after it hits closed loop once that it has a problem. The system goes into open loop and O2 values as well as LTFT and STFT flatline and the chugging idle ensues. As soon as I accel it comes back online.

I've seen some people note that the alternator could be at fault here. What's the chance of that?

Sorry for the long 1st post....

[behlinla]

Leaks past the upper and lower intake manifold gaskets are also a common problem on the Duratec, especially if the fuel trims improve once the engine warms up. Lots of info on this, so keep searching!