2001 Windstar hesitation

:banghead:
I've read lots of info here but am still baffled???
I used to have the P0171/P0174 codes and have fixed the intake seals and isolators. No more codes. New fuel filter, clean air filter, new plugs and wires too. I'm still having engine hesitation under load. Idles smooth. It gets much worse with the a/c on. Checked the TPS and readings rise smooth all within parameters. Checked the MAF and that seems fine too. Checked primary coil resistance and all read 1.0 ohm. Secondary all read about 11.4k ohms. No visual sign of arcing across coil towers. Put my scanner on and nothing, no codes. Replaced the pcv grommet too. Can't find any vacuum leaks either. What else could be causing this? Engine has about 135k miles. Trans rebuilt about 2 years ago. Any ideas?

:banghead:
I've read lots of info here but am still baffled???
I used to have the P0171/P0174 codes and have fixed the intake seals and isolators. No more codes. New fuel filter, clean air filter, new plugs and wires too. I'm still having engine hesitation under load. Idles smooth. It gets much worse with the a/c on. Checked the TPS and readings rise smooth all within parameters. Checked the MAF and that seems fine too. Checked primary coil resistance and all read 1.0 ohm. Secondary all read about 11.4k ohms. No visual sign of arcing across coil towers. Put my scanner on and nothing, no codes. Replaced the pcv grommet too. Can't find any vacuum leaks either. What else could be causing this? Engine has about 135k miles. Trans rebuilt about 2 years ago. Any ideas?

I would give a tried to the Fuel pump relay which is in the battery junction box, in the engine compartment; mine has failed not long time ago and gave me the same type of problem. This type of relay (same number) are used for other accessories ( wiper, front & rear, horn etc) you can see the number printed of the realys. You can just try to use one of another accessories to see what will happen. Anyway if this relay has never been changed on you Winnie, it would be a good idea to install a new one, some peoples here has ever replaced it a few time and I have paid about 7$ at a Ford dealership.

Tried switching relays. Same problem remains???

I have experienced similar problems, just recently as I travelled to Tennessee and back. I don't believe mine to be anything special. Runs normal, until I hit load under acceleration or climbing hills. Over drive ON or off, the van would just jerk and cut out. We shut everything off, and the problem lessened but persisted. We started noticed a small squeak just prior to the cut out. I believe I've isolated it to worn out bearings on the power steering pump. My steering fluid smells extremely burnt now as well, and it didn't prior to the trip. Have you checked for excessive wear/play on your pulleys?? I'll repost once I've replaced the pump and let you know if that fixes my hesitation/cut out. Anyways, with everything else checking normal on yours, I thought I'd suggest this to you.(Our Winnie is approaching 120K)

retnavy (http://www.automotiveforums.com/vbulletin/member.php?u=507505)
Im having the same problem now. I did my intake manifold gaskets and a couple upstream oxygen sensors to try and get rid of a P0420. Catalytic effiency below threshold bank one. All of that seemed to have worked but I have a bucking and hesitation under acceleration and load. Seemed worse with the air on. (96 3.8 Litre 190,000 miles.) I have read a few articles about this and seems its 3 possible things. TPS Throttle position sensor. Maf sensor and coil pack all three things have been addressed. However the tps is very diffficult to diagnose. For this reason I ordered a new tps. AT team Ford its $28.00. I tried disconnecting mine and it ran much better because it measures in such small increments it is easy to pas the bad spot and not realise. I also ordered a ccrm Constant Control Relay. It containes my fuel pump relay, Wot (wide open throttle relay) and controls the fan speed for the radiator cooling. I do not have a seperate fuel pump relay. My fans are acting up They dont turn on and off at the correct time. So long story short I will recieve them on wednesday and change them out and let you know what I find. My wires a re new plugs are new fuel filter new injectors cleaned and no codes. I thought to it might have been related to my converter because of high mileage. Only no codes for 300 miles after the oxygen sensor change. Ill post back what I find.

Well I received the tps, ccrm, and flex pipe. Replace the tps first little to no change. Replaced the ccrm had problem with cooling fan. Little change. Replaced the flex pipe. Had it done at Merlins Muffler $20.00 I bought the pipe. Seemed to help with the hesitation. May have been sucking in secondary air. It slightly hesitated once. It hesitsted and bucked before. Read an article that said to clean the Maf sensor using electrical contact cleaner. Ill try that to see if it solves the last of it. Hope this helps someone else.

Dirty fuel injectors are common with the windstar.
Berryman's B-12 Chemtool, 1 can in a tank of gasoline......maybe 2 tanks, each treated with a container of this.....should clean them up.

I posted close up pictures of the MAF unit.......if you hold it so that you are looking DOWN through the big opening.....and locate the small hole at one end of the plastic bar that goes across the middle of the opening........spray the non-residue electronic cleaner in that hole.....and let it run out the hole that is located at the other end......other side of the bar......it will flush the dirt out.

The cleaner is now often sold at auto part stores as "MAF" cleaner.
Many "contact" cleaners have a oil that is supposed to prevent oxidation......this would be BAD for the MAF as you want it totally clean......so be very careful to select a cleaner that leaves NO residue.

wiswind
Wiswind I took my maf sensor totally out of the air cleaner box and cleaned it. CCR Makes maf sensor cleaner. The little wires werent dirty just the screen and somehow a seed from a ash tree I believe got in there and stuck in the screen. It just enlarged one of the holes it didnt make it through. That did not seem to change anything either. I already put some Berrymans B12 in the tank no change yet. I changed my flex pipe to stop a small exhaust leak but now I hear the engine more and it sounds like its pinging. I was hoping the maf sensor would solve that no luck. Ill check the timing and see if its off. I know you cant change it you have to replace the pcm or try having it reprogrammed. It runs strong. The new flex pipe has a different design only one flex area. I questioned the dealer and he said it has been modefied.

Wiswind where did you get your dropping resistor from? The delaer said $40.00 discounted. Like $80.00 list. I was able to get the ccrm for $65.00 from the dealer.

Radiator dropping resistor, I got from the dealer.....don't remember the price.

Pinging can also be caused by carbon build up inside the cylinders.....as mentioned for the TSB for the upper intake manifold bolts for the 1999 and newer windstar.
Another, very likely cause is a small vaccum leak someplace that is causing the engine to run slightly lean....but not enough to light the CEL.

I have also found that a misfire can cause lean codes due to the PCM trying to compensate for the misfire.....again.....I can see this happening for a slight case that is not enough to light the CEL.
I tracked down a very slight miss for several months before it got severe enough to light the CEL.
Of course, once that took place, I had my answer as to the cause in hours.....which in my case was a dirty fuel injector.