My p0420 code

Yup, Cat isnt up to par code.. My O2s are lieing to my PCM.. I got a tired o2 today.. Just havent found which one just yet. They looked perfect monitoring them.. Just change them all hahah, but thats no fun, now is it.. You gotta love the challange.

Anyone ever have excessive pingging? Mine did have alot of pings, just wondering.. Is regular gas good enough anymore? hehe

Let me know..

Code less besides the 0420 today

Air temp 49
Engine temp 199
Everything looks good but didnt dig in yet..

how many run 87 or plus..??

Im sure It needs plugs, Cause I cant rememer when I did them, and thats bad of me..
My EGR does lower rpms when forced to open, Good sign of non clogged ports... If it sounds like a miss is the bad sign..
My EGR controller, well thats another day..
I do know a retarded o2 will make things ping away if its slow to respond back, stays high to long etc..
Intake leaks? Na, runs to good for that.. But it is a windie tho..
Either way, its still runs Tell the wife that all the time! She hates it when its her car tho haha..
Ill keep you guys posted, As I like helping others, because of the Overpriced Dealers, and Under paid Techs.

P0420 Downstream Oxygen sensor reporting low catalyst efficiency on Bank 1 (Rear Bank)
For those who find this post using the search function.

If you wonder if it is the sensor being tired.....you could swap the downstream sensors from side to side and see if the problem moves with the sensor (bad sensor) or stays the same place (catalytic converter).
Take note, if.....as was the case on my '96, one of those sensors is mounted into the back of the body of a catalytic converter....instead of the pipe.......that I had the sensor mounting ring turn right out of the thin metal body of the catalytic converter.......not a good situation if you are not planning to change the "Y" pipe.

If it is the sensor.....I think you are OK changing just 1 of the downstream sensors.....as they are only there to monitor the catalytic converters to make sure that they are working.
This application also has the oxygen sensor switching at a much lower rate than the upstream oxygen sensors need to switch.

Now.....if one were faced with needing to change an upstream sensor.......I would replace BOTH as a pair.....so that you have the SAME switching charactoristics......as they need to switch much faster.....and the upstream sensors are the ones used for fuel trim.

If you end up needed a "Y" pipe......not common....but then a defective downstream oxygen sensor is not real common either.
The OEM "Y" pipe for a 1999 3.8L NON california windstar lists for just over $1200.....millenniumn ford in seatle has it for just over $864, plus shipping.
That is about $400 cheaper on list and sale price than for my '96 3.8L.
The Walker "direct fit" for the 1999 3.8L is about $328....from Rock Auto.

If you end up needing a new oxygen sensor......I would get Motorcraft (available at Rock auto).
You can save a couple $$ by getting Bosch.

It is possible that the catalytic converter could cause pinging if it is causing back pressure, or no pressure.

HOWEVER....a common cause of pining on the 1999 3.8L windstar is covered in the TSB for P0171/174 sticky post at the top of this forum.
Folks have had the pinging crop up before getting any codes.
The 1999 will have BOTH the front valve cover (PCV baffle issue) AND the isolator bolt issue.
Clogged EGR ports go right along with that.
And the DPFE often is right in there as well.

If you have been drawing the excess oil in due to the less than effective baffle in the valve cover for the PCV valve......it can cause carbon build up inside the cylinders.
Which, you know about better than I do.......but for others reading this post.
The carbon build up inside the cylinders has the effect of increasing the compression......which causes pinging.
One solution that FORD came out with was included in a PCM "reflash"......which is a reprogram of the engine computer.....to delay the timing slightly to reduce the pinging.
My '96 3.8L still runs fine on 87 octane gasoline at just over 195K miles.

Now, if you have the vaccum leak that the breakdown of the isolator bolt sleeves causes......THAT is enough to cause pinging as you have a lean condition.

Ya, my intake is dry as a bone.. No sign of oil..
The intake Crap was done not to long ago.. And the van sits more then it runs anyway.. Lucky if it gets 2000 miles a year Tho these last four weeks we have been driving it more waiting for a trans failure which is not gonna happen I guess.. Still Waiting to get an appointment over at the trans shop just so I can use the ford trans tool..

I was criusing today at 45ish, And I baby it, Never in a rush because Of my Electric Wheelchair is like 6mph and Im used to that speed.. Wife always says Im a old man driving.. Anyway, It pinged some getting up to speed, and the light came on.. I was happy to see a light Because OF my Other Transmission thingy, but was 6 miles away from my scanner..
Didnt change running conditions at all and did notice more pinging after. PCM making its own rules once the light is on...
I Gave it a bit more throttle, Not much a 1/4 more throttle then Grandpa speeds, and a slight harder accel the ping is gone. So maybe, The ping itself may have set the code "lean Conditions etc".. I had it come on once before like 3 months ago, but I didnt scan it.. And I did the battery so everything got cleared.. It may have been the same code before...

I gotta run it around with the scanner monitoring and recording and see where the O2s are.. And see if the egr controller is good, and not over working it.. I may just unplug the egr one day just to see what changes for the Heck of it. Simple check and it rules the egr and control out.

Got my scanner once home, "VAN Still running outside so I didnt lose any codes!!! HAHA..

You gotta love the Big F..

We have been driving this tank-hog around, even the same route when the light turned on and NADA.. No codes no light no nothing.. You gotta love it..
300 miles
I mean, come on.. Give me something to work with here Ford!! Runs to good to even waste my time now.. If you know what I mean..

Oh the trans now has 1500 miles on it and its still going. Who loves ther van? LOL

My 2001 Windstar had the problem late last year of misfiring and I changed sensors everywhere (except O2), changed plugs, wires, did the entire intake port cleaning and replacing the valve cover, etc - it turned out to be a bad coil.

However now I have a check-engine light and I just got it read at Auto Zone - it came up as P0420. Dunno where to start! Maybe change the O2 sensors? Perhaps replace both cats? There's a rattling sound coming from the passenger side underneath that sounds like something is loose on the outside and not the inside. I had a rattling cat on an '85 Escort a few years back and I solved it by buying a big clamp to go around the cat and tightened it up. This sounds almost the same.

Man I just love this friggin' Windstar!

In the post I have above, I suggested switching the downstream Oxygen sensors from side to side.
Downstream sensors are the ones AFTER the catalytic converter.
If the code moves to the other converter, then you know it was the oxygen sensor.
If the code comes back at the SAME converter.....then you need a new "Y" pipe....(this is after having the original code cleared......as the codes stay for a while before clearing on their own).
Hopefully you will be lucky.....and only need a new sensor.....not likely....but certainly worth a try.

For the rattle.......if you look in the pictures, that the link in my signature takes you to, you will see a picture of just what you mention with the big clamps.
I got mine in the pluming department......a extra big hose clamp......it takes 2 clamps for 1 converter.
That will take care of the rattle if it is caused by a broken spot weld on a heat shield.
It is also possible that the bolt at the transmission......that holds the "Y" pipe is loose.

Thanks wiswind - I'll give that a shot!

I saw your photos - lots of great info there too! I may need to replace my driver's side window motor too. On my '97 Thunderbird passenger side window the glass came off the attachment to the motor. I can hear the motor working but the glass doesn't move - it stays up. Same thing happened on my '88 TBird! The glass was attached to the motor arms by some white plastic tabs that appeared to have been glued to the bottom of the glass! I haven't pulled my passenger door panel on my '97 to see if it's the same setup but I'm betting it is. If so I may use some epoxy to re-attach - but I fear that one or both of the plastic tabs may have broken or cracked off. Why the hell do they do it that way?