Help! Six check engine codes, and more.

1998 Windstar 3.8 engine 195,000 miles

Very quickly (within a mile) after the engine was missing somewhat, it seemed to lose a lot of power-- perhaps one bank- and a noise like a broken mufffler came on, and the check engine light, which had been on for a while, was now flashing.
I have a code reader in the car, and six codes came up-- here they are, with the id's I found on other sites, in the order shown on the reader (which
may be the order that the problem occurred, most recent first)

P1538 Intake manifold runner control stuck open
P1131 Lack of upstream heated oxygen sensor switch
P0303 Cylinder 3 misfire
P0302 Cylinder 2 misfire
P0171, 174 Banks 1 and 2 running lean
I have had the P 171 consistently for a while, the 174 less often, and the misfires, occasionally, but never actually felt any misfiring, and the car seemed to be running OK. About a year ago I replaced one of the IMR controls, but the code(s) returned after a while.

I was able to get the car into a street parking space, but have to move it soon; after stopping, I was able to start it again. But I am about
25 miles from home where I can check it out further, or get it to a mechanic. Is there any risk of damage, or total breakdown if I attempt to
drive it that distance (if one bank is gone, might the other go as well?)

Could this have been caused by 1) bad gas-- I had filled up a near empty tank at an unfamiliar station yesterday 2) not fixing the running lean codes sooner 3) the recent recall notice issue?

It is dark now, and I can't really seen anything, but will be able to see more tomorrow, but I only have very basic tools in the car.

Unmetered air leaks can cause lean codes + misfiring, because of Age and mileage suspect rubber, plastic, or a bad seal causing the problem.

I'am suspecting a bad PCV system causing an unmetered air leak.

1) Isolate the PCV system from the air duct work going to the throttle body.
2) Get some duck tape, and block the open port hole on the air duct work.

If not the PCV system, you need to isolate the EGR system some how.

A bad EGR system can cause lean codes + misfiring.

The 2 misfire codes are the cause of the flashing CEL.
If the misfire were to be caused by a lack of spark, then you would be putting raw gasoline into the exhaust.....and on into the catalytic converter for the offending cylinder(s).
Raw fuel into a catalytic converter will cause it to become very hot......and damage it.
This is the reason that the CEL flashes for a misfire code.
The PCM does not know what caused the misfire............which can be caused by lack of fuel, and other causes.

I suspect that the IMRC code 'could' be caused by the misfire codes.
This past summer, I got a IMRC code when I was having a issue with the vehicle speed sensor.......
I had the speed sensor replaced.......and the IMRC code never came back.
In other words, one problem can cause a NUMBER of other things to show up.

As advised above.....verify that you don't have a defective vaccum line.....there are a lot of possible suspects......
PCV line from the top of the upper intake manifold.....next to the throttle body.......that elbow cracked on mine.....(got one from AutoZone in the "Help" section....and cut it to fit), follow the line to the BACK valve cover and check all things along the way, including the connection to the PCV valve.

If you suspect the EGR system.....you can disconnec and plug the vaccum line that goes to the top of the EGR valve.....which will disable the EGR system.
THIS IS ONLY A TEMPORARY TEST......not something to leave this way, as that would cause problems if done long term.
Of course, this will cause a code for insufficient EGR flow......
Clogged EGR ports in the lower intake manifold can cause misfire codes......usually P0303 and/or P0304.
I had ONLY 1 of those.....no other codes from clogged EGR ports.
From all my reading on here......as soon as I saw the flashing CEL and felt the misfire......under the driving conditions......I knew right away that it was the EGR ports.

The big vaccum line from the back of the upper intake manifold to the power brake booster.....has been known to get loose at one end.

Misfire and lean codes can also be caused by dirty fuel injectors.
Berryman's B12 Chemtool in the gasoline tank is the only cleaner that I have found to solve that.
However, that takes time.

Wiswind--

Thanks for your detailed advice. I now have some new information, and am relating some old info that is not entirely consistent with your analysis.

First, I was able to look under the hood in daylight, and immediately saw that the little plastic retainer clip on one of the IMR controls (front) had come off, and the rod was no longer in the opening for it-- so the control had remained in the open position, and could not close under any circumstances. This clearly would have caused the 1538 code; possibly the 1131, but I don't know enough about that condition.

Re your belief that the misfires caused the flashing CEL-- In the past few months, when I havechecked the code reader (after clearing, and then seeing the CEL coming on again after a while), there sometimes was one misfire code (I don't remember which), but the CEL had not been flashing. Possibly it started to flash this time because two different cylinders were misfiring instead of just one. I think-- just a guess-- that the flashing started when the 1538 and/or the 1131 was activated.

Also, I don't think the IMRC codes were caused by the misfires-- because I have had those codes for a long time-- months-- before I began seeing any misfire code. Is it possible that the misfires have been cause by the IMRC problems-- or both are a result of some vacuum leak?

I also had a speed sensor problem, and had it replaced, a year ago-- but I did not see any connection between that and the IMRC codes.

I haven't been able to get underneath to look at what's causing the loud muffler sound; I will get the car to a muffler shop, in a couple of days when it has warmed up around here, and I don't need to drive it before then. Not clear though why any of the code problems should cause a muffler to go bad-- running extra hot, perhaps?

Getting back to the IMRC retainer: The clip,which I retrieved, is shot-- the tiny pressure protrusions on it have broken off, so if I put it back on, it wouldn't stay on for very long. Not clear why they broke off-- perhaps just old age and a lot of heat? One possible factor-- in the 25 mile drive just before this incident, I was driving quite fast for a stretch, likely over 3000 RPM, so the IMRC might have tried to open again, and that's when the problem might have occurred.

When I replaced the back IMRC some time ago (over a year), I lost the only clip
that came in the package with the new one, so I ended up securing the rod with a
small cable tie, pulled very tight around the rod. This has held up-- over a year now, and I will do the same with the problem one. (I did put the IMRC rod back in the slot, without the clip, and started the engine, and both runner controls appear to be working properly-- they looked
fully closed.

Once I get the muffler taken care of, I will check the vacuum lines, but perhaps proceed to get an overdue tune up first; I really don't have the experience or the equipment to do a complete tune-up myself.

Any other thoughts or suggestions would be welcome and appreciated, and
thanks again for spending time to help me out.

A good smoke test will find your unmetered Air leaks!

danielstur-

What is a smoke test, and how do you do it?

Thanks

The machine looks like a mini shop vac, that produces smoke, it's forces smoke through the air box, and any leaks in the air system will be visable.It works great for checking unmetered air leaks in the Intake, EGR & PCV systems.
Do a Google ''Youtube Auto smoke test''