Miss/bucking at low speed & on incline

[wiswind]

I would do the check you mentioned a few posts up.....pull and plug the vaccum line that connects to the top of the EGR valve.
NOTE, This should set a failure code of insufficient EGR flow as you have disabled the EGR valve from opening.

With the EGR valve disconnected.....take the vehicle for a drive.....
If the problem still happens.....it is not caused by the EGR system. (sticking EGR valve is rare on the windstar)
If the problem does not happen.....you are still battling a EGR problem.

As you are wondering if the problem is the transmission (or other cause) it is always good practice to re-verify the system that is acting up.

[Windywoes]

Thanks, Wiswind. It is an easy troubleshoot so I will give it a try.

Once thing I have noticed is that this problem mostly happens after making a turn and then going up an incline in 4th at low RPM. Rarely does it happen just going straight up an incline.

[garync1]

My issue went away when I changed out my spark plugs from 765 to 105's Ones a half thread and the other full thread.. I sent you back a return PM.. Hope you get it.. I also hope the spark plugs are your problem.. Good luck..Just make sure they are full threaded spark plugs..


Gary

[Windywoes]

Followed Andrew's guide for troubleshooting the DPFE and found the voltage did change with engine speed so I think the DPFE is operating correctly. Engine stalled when applying full vacuum to EGR so I think EGR is working. Also looked at 4 of 6 plugs and found them properly gapped and in very good condition (only 32,000 on them).

Next I will try Gary's suggestion of changing out the APP 765 plugs for some APP 105 full thread plugs. If that does not work I am taking Wiswind's advice and going inside to clean EGR ports. I am determined to solve the bucking/missing problem. Other than that Windy runs great.

Wiswind: if you are reading this how much did all the parts cost to do an EGR port clean job? Gaskets, retainer bolts, washers, etc?

[tomj76]

I paid the Ford dealership to clean my EGR ports the first time. The only materials they charged me for were the upper manifold gaskets (six rubber gaskets) and some carb cleaner. The charge for the materials was under $25, but the total bill was ~$400! Since then, when I've cleaned my EGR ports I have only replaced the gaskets once, and only because it was before I tried to re-use the old ones. I've cleaned them at least three times since the first time, over the last six or seven years.

It's not a hard "repair" to make, I think it takes me about 2 hrs. I believe I do it with the cowl removed. I remove the vacuum lines (be careful not to break any of them!), remove the intake bellows, then unbolt the 12 or so upper intake bolts. I roll the intake manifold over and lay it "on" the battery while I clean the ports. I use a shop vac next to each port while using a small drill bit to remove the build up on each port. Carb cleaner will let me get the rest of the residue off and clean up the lower manifold sealing surfaces. Then I reassemble.

When my EGR ports have needed cleaned, I've seen misfiring at idle or misfiring while highway crusing. Another symptom I recently experienced was misfiring only after initial warm-up, after shutting down the engine a short time (for example the time to refuel) then misfiring after re-start, even to the point of continously misfiring for an entire 10 mile trip.

[wiswind]

I have a '96, which has re-usable upper intake manifold gaskets and does NOT have the isolator bolt issue.
SO, it requires NO parts to clean the EGR ports on the 1996-1998.
I left the accellerator cable connected and removed the throttle body....and just set it aside.
Lots of messing around......but the only investment was time and some cleaner.

[Windywoes]

Thanks for the info, Tom & Wiswind.

Tom: what year is your Windstar?

[tomj76]

I have a '96 Windstar, 3.8 L. I'm sorry I didn't mention that point.

[kikillo01]

I, had the same problm w my 01 windstar live in Puerto Rico bad roads too many hills I change the plugs, thewires, pdef trany range switch or sensor; also didi the seals in the intake egr ports and none of this cured the problem untill I, got a repair manuel check the ign coil acording w the manuel and that was the problem the resistance in the #1 was not w specificatios changed it 19 months ago my van runs like a new one w 198.000 miles by the way need to thank 12 onz wis windand the rest of the guys in the forum you guys are the BEST say it out loud

[Windywoes]

If today's EGR port cleaning does not fix the problem (so far it is running much better) then my next course of action is to change the 765 plugs to 105's and then check the coil pack much closer than I already have. I appreciate your inputs all the way from Puerto Rico.

[wiswind]

Coil pack seems to be a common failure from reading the number of posts about it.

I don't know about the newer windstars, but the older ones......as I have found with my '96 tend to build up crud inside the "end cap" on the fuel injectors.
The BEST way that I have found to clean them is to add Berryman's B-12 Chemtool to the gasoline tank.
Mine tend to start by causing a slight miss.....which gradually gets worse over time.
When it first happened, I spend months checking, cleaning, and replacing.......until it got bad enough to cause the CEL to come on.....which lead me straight to cylinder #2 (back middle....of course).
I bought a new fuel injector as switching spark plugs did not change the problem (already had a new coil and wires and plugs and DPFE and EGR valve.......and a couple other things).
Once I removed the fuel injector and looked up inside the end cap....I could see crud up in there.....I posted a couple picture to try to show it....but it does not show up well in the pictures.
I had already tried MANY different cleaners......The problem came back a couple more times after many miles........and now run the Berryman's B-12 Chemtool through about 3 or 4 times a year.
Nice thing is.....it is one of the least expensive of the products on the "Wall of fuel system / injector / carborator cleaners" at the auto part stores.
Right now, it is in a metal can.......check to make sure you get the correct amount for your gasoline tank, which is either 20 or 25 gallons.....

Lots of messing around on my part several different times.....but I have the solution down pat now...............

[MARZBX157]

Wasnt the APP 105 a problem on the Windstar and upgraded to the APP 765? I just changed out the plugs on my 2000 and I used the 765 and my van is running great.

[Windywoes]

Some said the opposite: 765's were passe and the 105's were now the acceptable plug. I think Rock Auto even lists them that way.

Thanks also for the advice on dirty injectors. I will add it to the list of "things to try" if cleaning the EGR ports did not help. I have run 2 cans of B12 through Windy in the past 9 months.

Update:
ALAS! Just took her for another test drive and the miss is back. Now it is on to the plugs and the coil pack. At least she is running better at lower RPM's

[MARZBX157]

Yup, I just some how got it backwards about the plugs, I just hope I don't have any future problems with the Autolite 765 plugs I've installed. The van is running smoother than before.

Also, I have to say I like the systematic approach you are taking in finding the problem, going from one thing to the other in steps. Good Luck