98 Windstar P0171/174 runs poorly w/ warm

I have spent hours reading post on this site. There is a lot of good work here. I hope that someone will be able to help me.
I have a 98 Windstar 117,000 miles / 3.8… About 2 months ago, the CIL came on and I took it to a mechanic. He said that the O2 sensors were bad and changed all the O2 sensors. Everything appeared to be OK.

However, the CIL came on a few weeks ago. I checked the code and am getting P0171 & P0174 code (running lean). Soon after, it began idling a little rough and it would occasionally die if I take a corner to fast. Over the last week it seems to idle fine and drive fine after cold start. But after it heats up and we turn it off, maybe to run into the grocery, it begins to idle rough and we are barely able to drive it. It coughs and sputters horribly after you put it in gear. On a scale of 1 to 10 the acceleration is a 2. Many of the post I read have to do with idling poorly until the engine warms up, I have not seen any were the problem occurs only after the engine is heated, and the problem only arises after a restart…..Any ideas?

Last night I replaced the air filter, fuel filter, PCV valve….It did it again. After reading post here, I cleaned the IAC, still no luck……Please help !!

Try these things to try to narrow down the problem. To confirm that the problem is only after a restart after the car is warmed up and not when it is just restarted, start the car cold and let it idle for a minute and then shut it off and then restart. Next you said that after a warm restart, it would idle rough when put in gear. Does this mean that it idles OK until it it put in gear or does it idle rough before and after it is put in gear. I could be the EGR valve could be sticking or the EGR sensor could be bad. You could try to run the car for a day with the vacuum to the EGR valve disconnected and see if it runs OK. Dont forget to plug the disconnected vacuum lines.

Thanks for your reply.

After a cold start it seems to run fine for as long as you drive it. As you say, I can start it, let it run and turn it off. If I restart it again after a few moments, it seems to still run fine. It is only after it has been run and sets for 20 mins-2 hrs that it has its problems. But it is not even completed consistent it that. Seems to be intermittent, but it has never happened from a cold start. It will then idle poorly, and when put into gear, it gets even worse (I mean REALLY bad) and becomes virtually un-drivable (someone I know describes it as a vapor lock (?)). I will try what you suggested with removing the EGR vacuum line and plug the line…..If it runs better after that, does it mean its the problem?

I would not rule out the IAC valve yet because they are tricky to clean because they do not really get dirty but the mechanisms in the IAC get sticky. Remove the valve. Inside you will see a metal rod with a plastic disk attached to it. With a small platsic or wooden stick, push on the plasic disk and the metal rod should move with it. It will not move far, only about 2 or 3 millimeters. There is a spring that you can't see attached to the other end of the metal rod. This spring should quickly push the rod back to the original position when you stop pushing on the disk. If you can move the plastic disk but it sticks in place or moves back slowly, then you need to free up the sticky metal rod. Place only a few drops of WD40 directly on the metal rod and not on the plastic disk. Use your stick to push the plastic disk back and forth over and over until the mechanism moves freely and moves back to the original position quickly without sticking.

I had the same problems with the same error codes. Clean out your IAC and see what happens. It fixed my problem.

Time for an update.
After cleaning everything I could, IAC, MAF, EGR, I was still having the same problem. Finally, I broke down and took the van into a mechanic.

I drove away from the mechanics with a new fuel pump and $500 less in our checking account. The van was idling and accelerating much better and we thought we were in the clear. After leaving the garage, and driving the 4 miles to pick the kids up from school and go home the van died 6 times. Each time it was when the van was coasting or coming to a stop. Needless to say, I was very disappointed and took the van back to the mechanic the next morning wanting answers. After they looked at it, I was told that it was definitely the IAC and needed it to be replaced. Several hours later I received a call from the mechanic explaining that they replaced the IAC and it did not make any difference. However, they had done some research and came upon a TSB for the 98 Windstar having the same symptoms. I don’t have the number for it on hand, but can find it if anyone needs. The TSB states that the PCM needs to be reprogrammed, which can only be done at the dealers. I dropping another $70 at the dealers to have it reprogrammed (which takes about and hour). Finally, the van is now running smoother than I can ever remember it running.

Thanks to all of you for your help in trying to come up with a fix for this. It was all good advise and I am learning a great deal about what to watch for with my van. Unfortunately, It is scary to see all the problems that seem to be occurring with the Windstars…. Kind of make you wonder…….

TKSWA, I would like the TSB number. I'm certain that our van is doing the same thing at about the same mileage. The trans also clunks, yours too? IMHO, the auto manufacturers could have perfected the car in the 60's. Too bad we don't have enough input to force them to simplify for the sake of maintenance and dependability!!! We don't need all of these sensors. I despise how engineers measure common tools and then design cars so that your tools won't fit.

Thanks,
GSR

Stared running really bad.. Had to stay at continues speed in order to keep it running. Dealer said coil pack. replaced it along w/ plugs and plug wires, fuel injector in #5. runs real bad when you turn the ac on. Iread the above post and I am going to try your suggestions, do you think it could be the same thing??

I've got the exact same problem as you. I'd really like to find out what the TSB number was that did the trick for you?

All I can find for mine (2002) is this one ... or maybe that TSB was only for your model year?

http://www.ford-trucks.com/tsb/tsb.php/m-FORD/d-WINDSTAR/y-2002/t-042107

Thanks!

The TSB states that the PCM needs to be reprogrammed, which can only be done at the dealers. I dropping another $70 at the dealers to have it reprogrammed (which takes about and hour). Finally, the van is now running smoother than I can ever remember it running.

I have the same problem on the same model year and I've replaced IAC, EGR, PCV, TPS, intake gaskets... the list goes on, still the same problem.

Good to know now that I can have fixed for $70.

(I probably have the cleanest windstar engine in Georgia now though)

i have a 1999 same kind of thing but mine misses andpops and runs like shit for 2 minutes then it runs finemap, maf, plugs cap rotor wires all replaced even ecm, when you strat it it acts like it lean or missing like timing , you step on the gas and it pops and spuuters and sounds like many lil mini back fires, let it run for aprox 2 minutes and its so smooth and runs great

I Am Having Sort Of The Same Problem, My 98 Winstar, Starts Fine Cold Most Of The Time, Sometimes You Have To Start It 4 Or 5 Times Then It Runs, After Its Warm, Or You Drive It A Bit Then Shut It Off, It Restarts And Sits There Jumping Up And Down On The Idle, Real Bad. If You Try To Drive Off, It Chugs Along, Once You Get Past That It Runs Ok, Considering It Has 172,000 Miles On It. Other Than A Small Miss, It Still Runs Alright Though. Original Trans Double Shifted Into 2nd, After A Fight With The Dealer We Got That Fixed, And The 2nd Trans Is Now Acting Up, But We Put More Miles On This One Than The First. Overdrive Light Comes On, And Then The Tach Jumps From 2,200 To 3,500 Back And Forth.