2003 Windstar stumbles at idle

165K the problem will go away temporarily when revving the motor, and turning off accessories helps. I have no codes present. I was leaning toward IAC or DPFE. Coil, plugs and wires are new. I've done the intake isolator bolt fix as well, and cleaned the EGR ports.

Rule #1 for Windstar idle problems is "Clean the IAC". This procedure documents it rather nicely:

http://leckemby.net/windstar/windstar02.html

It's really very easy. It probably takes longer to read the procedure than to complete it...

ditto on what Phil says.....

Yep. I used that procedure to cure the idle stumbling problem on our 2000 Winnie. (with 120k ). Cured it right up.

I replaced the IAC, and that was successful as far as curing the idle issue. Today, however, one of the hoses going to the DPFE unit blew off the exhaust tube and was nowhere to be found. I heard it, looked around the engine bay and noticed hot pulses of exhaust coming from the little tube where the rubber hose blew off. Stopped by an auto parts store, purchased a new tube and DPFE sensor just to be safe. Installed them and drove another 50 miles to find the OTHER hose was blown off the exhaust tube. The van also seems noticeably down on power, AND I pulled a PO430 catalyst below threshold code last week. All of this is screaming to me PLUGGED CONVERTER(S). With 168K on the odo, does everyone agree? I thought the DPFE worked off vacuum and not exhaust pressure? Should there be pulses of exhaust blowing those tubes off?

There will be some slight amount of pressure at the DPFE hoses....as they both are connected to the exhaust.
HOWEVER, they should not be blowing off........that sounds like too much pressure.
Reading through your problem, I don't see anything about the hoses being touched before this happened.
Take note that the hoses are slightly different sizes.

Double check to make sure that there is nothing else causing a restriction to your exhaust before shelling out $$$ for a new Catalytic converter assembly.

Rockauto has the Walker Direct Fit for about $373 and the Eastern for about $354.
Best would be OEM....which will be a LOT more.

You will need a new gasket for the junction between the "Y" pipe and the flex pipe.
You may need some new bolts & nuts for the same connection.

If you do the job yourself, support the front end of the flex pipe, which connects between the "Y" pipe (converter assembly) and the muffler.
You can use a loop of wire, etc to hold it up.
Leaving the flex pipe dangle will damage the braiding.......
That will save you from another $100+ for the flex pipe.

As with any exhaust work......changing the "Y" pipe is not fun.
Soak the manifold stud nuts and other nuts & bolts with PBlaster.....let them sit.

Thanks for all the replies, guys. I will be removing the Y pipe and flex pipe and taking a look-see. Will let you know what I find.

The flex pipe on my '96 was not interested in separating from the pipe on the muffler.....was going to need to be cut off.
You may or may not end up with the same on your 2003.
I would loop a wire around the front of the flex pipe....and secure it to something above it on the vehicle.....to keep it from being stressed.

I shot my laser temperature gun at the converters after the motor had been run and warmed up. Passenger side converter read 253F, drivers side read 345F. I think I found the issue. Rock Auto is sending me the Walker replacement Y-pipe and flex pipe, as the wire mesh has separated from the collar. I've been soaking the nuts and the flex pipe where it connects to the muffler in PB Blaster for 3 days, so I'm hoping for good results. I have 4 new O2 sensors to go in and a new gasket for the flex-Y junction. Anything I may have missed?

I had problems removing the bolts on my '96. PB Blaster and others didn't work. It took heat on the flange, until it was black cherry hot to break the bolts free.

On the OE Y-pipe, the flange was tapped. On the replacement the flange was a through hole. I also had issues because O2 sensor location on the passenger side was further back, and the wire didn't reach.

embalmer - you also need bandaids ... and beer

embalmer - you also need bandaids ... and beer

Beer will be consumed in quantities. I've had a new transmission installed which required dropping the subframe. I checked the nuts for the manifolds and they are NOT rusted, look brand new. The new Y-pipe and flex pipe are due here Tuesday, I will report after that.

On another note - the pipes are so clogged right now that I cannot drive the car at all. Both DPFE hoses are blowing off so I decided to park it, and luckily, through my work I have access for my wife to drive another car until I get this fixed. Wish me luck!

Last note - I have in the past dropped many K-member out of my T-Bird and pulled other motors, so I'm not new to wrenching on cars. Assuming no real issues (rusted bolts, etc.) I should have this thing done by Thursday at the latest. Next thing is figuring which coolant pipe is leaking from above the water pump.

In 4 hours tonight with my 11 year old helping I dropped the Y-pipe and flex pipe, put all new O2 sensors in the new pipes, and reinstalled them. I'm glad I sprayed the nuts with penetrant, because a couple of them were tough even with the breaker bar. An impact made short work of them once they were loose. You definitely need a helper when installing the new pipe.

The front converter was completely melted, and when I shook it chunks came out. I reset the battery with the new sensors, took her for a drive and WHAT a difference! Pics below.

http://i77.photobucket.com/albums/j56/faxisis/100_3863.jpg

http://i77.photobucket.com/albums/j56/faxisis/100_3862.jpg

http://i77.photobucket.com/albums/j56/faxisis/100_3864.jpg

http://i77.photobucket.com/albums/j56/faxisis/100_3865.jpg