2001 Deathstar - Shifting Problem?

3.8L Sport 128,000 km (no towing) and new Mobil 1 Syn ATF and filter in the tranny within last two months. Noticed that when driving between 80 and 100km/hr that the van hesitates/jerks when applying load (kind of bogs down for a second) . I think it is trying to shift up because it seems to happen when the RPMs are at about 1800 and I press the gas lightly to speed up. However, it only happens when we are going up an incline, i.e. there is some loading on the engine. If we are going on a flat or downhill it doesn't happen. This may not be anything to do with the tranny, but it is all I can think of based on what is happening. By the way, it doesn't happen at lower speeds at similar RPMs. I also have completed the P0174 grommet/gasket repairs. Any thoughts?

FIRST thing that I would do is to double check the transmission fluid level.
If the level is slightly low.....it could take up some air when not on level ground.....or when you go around a corner.
So.....this is a possibility......and the easiest thing to do.

Also, when you changed the filter.....did you get the gasket out of the bore?....It is normal for the round gasket from the old filter to STAY in the bore on the transmission when you pull it out.
This is NOT the pan gasket, but the small round gasket that is on the neck of the transmission filter....the part that presses up into the transmission bore.
The pictures that the link in my signature takes you to have a series that show step by step the fluid and filter process....and I show the filter gasket issue in detail.
If the old gasket is still up in there....the new filter will not fully seat...and you could take up some air.

If you still have the old filter.....you could look at it to see if the gasket is still on it.......if it is not.....then you know where it is.
Use my pictures to compare.

Thanks for the input. I did check the level and it appears to be full, maybe even a little too high. Also, I did use your pictures and advice when changing the tranny filter (thanks) and the o-ring did get stuck and I did have to pull it out with pliers. I was reading another thread "EGR Mystery" and the comments there sound similar tot he problem I am having, so I will watch the results of that. Can you tell me what the DPFE does and how it works? I see a lot of oil around the top cover on mine and when I did the P0174 fix on my sister's 02 Windstar, she had the same thing. I cleaned up hers and replaced the rubber vaccuum elbow, which was loose, but maybe there is something else wrong inside the DPFE? By the way, yesterday, the check engine light came on again! I have doen the P0174 fix. I do not have a code reader so I will have to check around and see if anyone I know has one and see what the code is.

I was just reading thru the Ford Service Manual and now I have a better understanding of what I am looking at, so just to clarify things; the elbow I am refereing to is the vacuum line off the EGR valve. It was leaking oil onto the top of the valve on both my sister's and my van. I replaced the one on my sister's van, but when I tried to get a new elbow today, Ford wants to sell you a whole bunch of parts even though you only need the one, so I didn't get it. I thought I would check around first. Too bad the dealership where my sister lives didn't give her two!

The DPFE measures the actual flow through the EGR tube.
The PCM then modulates the EGR valve to maintain the desired flow through the EGR tube.

I would get the code(s) read.
If you are in the USA, you can do this for FREE at AutoZone, Advance Auto, and many other auto part stores.
Make SURE that you get the actual numeric code.....not just a description.

The PCM modulates the EGR valve by regulating the vaccum applied to the EGR valve through the vaccum line that connects to the top of it.
There is a electrical solenoid on the back side of the engine......that has an electrical part....connected to the PCM (computer), and a vaccum line going through it.
The solenoid opens and closes to apply more or less vaccum to the EGR valve.....causing the EGR valve to open and close in the amount needed to get the desired EGR flow.

One test that you can do is to TEMPORARILY remove and plug the vaccum line that goes to the EGR valve.....take the vehicle for a drive......if the symptoms you are seeing go away....then it is caused by the EGR system.
If the symptoms do NOT go away....then it is something else.
NOTE......this test should cause the Check Engine Light to come ON....with a code stored that indicates insufficient EGR flow.......which is caused by the disabling the EGR valve from opening.

I am in Canada, but thanks anyway. Great explanation, really usueful. I will get the codes and have a look around for what they mean. Thanks again.

OK, I finaly got the engine code read and it is P0401. From what I understand, this means low EGR air flow. So what I am thinking (please correct me if I am wrong) is that either the vaccuum hose from the EGR to the EGR Valve is plugged OR the solenoid is not working OR the DPFE needs to be replaced as it is not measuring correctly.

If this is reasonable to thikn, then how do I test these things to prove out where the problem is coming from?

Question: Is the small plastic hose from the back of the EGR that comes over to the EGR valve supposed to be restricted from flow when the engine is off? I pulled the hose off at the valve and tried sucking air through from the EGR, but ti seemed to be restricted and difficult to get any flow. I was wondering if that is because the solenoid would be closed when the engine is off? I could remove the cowel etc and take the hose right out and check again, but I haven't yet.

Question: I just realized that the EGR hose to the EGR valve, having a rubber elbow of the top of the valve is fairly loose; so could it be that with a vacuum leak at the elbow, there is insufficent vaccuum to move the EGR valve open meaning I would get a P0401 code, i.e. low air flow?

You may have found it!

Also check the two rubber hoses that connect the DPFE sensor to the EGR tube ... they take a beating. The DPFE sensor itself also has a high failure rate ... especially the metal body versions.

I have other DPFE unit (the non metal one) and I did check it to see if it was loose, but it wasn't.

I may have fixed the problem. Last night I took a zap strap and tied it around the rubber elbow connection to the EGR valve. I pulled it tight, then removed the ebow from the EGR valve, pulled the strap a little tighter, then pushed the elbow back on the valve. I then took the van for about a 20 minute drive and NO MORE BUCKING!!! It shifted smooth as can be. I am keeping my fingers crossed. After testing it, I reset the engine light and told my wife to let me know if it bucks again or the engine light comes back on. Hopefully that was it!

I will report back maybe next week to see if it is still running well.

CEL came back on and I have one or two small bucks when shifting again. Seems to have improved significantly, but I will report back when I get the code again and see if there is something new instead of the P0401.

I would remove the two hoses that connect the EGR tube to the DPFE sensor ... see if either is cracked anywhere or filled with gunk. If no problem with the hoses, I would try a new DPFE sensor ...or swap one off of a matching vehicle.

Thanks, but I have the older style sensor that is basically a rubber block instead of the metal one and it has hard piping up from the tube to the sensor as opposed to the newer ones with the rubber hoses. I will pull the sensor off again and this time see if I can shine a light down there to confirm there is no pluggage. Is there any way to test the sensor to see if it is faulty?

I know the model year is different, but take a look at the photos of the DPFE sensor here:
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http://www.autozone.com/R,1934807/vehicleId,2333902/initialAction,partProductDetail/store,985/partType,00666/shopping/partProductDetail.htm
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... is that what you are looking at?

This is for model year 2001:
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http://www.autozone.com/R,710980/vehicleId,2627001/initialAction,partProductDetail/store,985/partType,00666/shopping/partProductDetail.htm
.
??

The desciption of the picture says that is for the Ford trucks. Any way, mine does not look like either. I know exactly what you are talking about because my sister's 2002 has the one you are showing in the pictures. Mine has the mounting holes in the EGR clam shell housing, but no metal block. There is a rubber block mounted on the pipes coming up from the EGR air flow pipe with the wire harness off of it. I have not had time yet to open it up and have a look for any plugging, but I bought a code reader today, so at least it will be easier to self diagnose the problem. This P0401 code can mean a whole bunch of different things. What a pain in the butt.

I got the same code up again, P0401. I think I am going to see if I can remove the EGR valve, hoses and DPFE and look for any cracks or crdu build up. Can anyone tell me how to remove the valve and if there is a way to test it to ensure it is good? I hate to buy things just for the sake of eliminating them.

Except in the minds of the salepersons at parts stores, the EGR valve almost never, never fails!! But they each sell a basket-load of them each month, I'd bet. They get rusty. They can be difficult to remove/install. Pricey.


The DPFE sensor however, fails often (for Ford). Pricey, but maybe less than the EGR. Its easy to remove (two small screws, two hoses, one elect connector, etc. You could do a quick swap out with someone who has a similar vehicle .. if you are lucky enough to know such a person.