Ford Windstar 2000 not idling smoothly

I Have a Ford Winstar 2000 slx, after 50 000 miles, an idling problem began. After running it for 2-3 20 minute periods it began to idle irradically reving high and low finally cutting out. I wouldn't be able to start it. Calling the dealer he said wait 1/2 hr. then retry it should start up. Bring it in and we'll replace the fuel pump. The fuel pump has been replaced 1 more time since then in March '04. Now it's back in for the same thing. What's up with that? Dealer guarrenties the work for 1 yr so the second occurance was covered and I 'm hoping this one will be too. But if the fuel pump is the problem and it's being repalced, to now twice am I going to have to replace this thing every 6 months? Is there an underlying problem causing this. I get Van in for regular oil & needed tune ups when needed so neglect isn't the problem. I travel 300 miles 1 a month, city driving in between long distance trips. I'd like to keep it till nuts and bolts drop off so I'm interested in caring for the little problems before they become big ones.

Has the fuel pump relay been changed? $10.

there is a sensor on the throtle body area going into the intake area.
unplug it and clean the connects and plug it back in if you first unplug it and your idle does not drop like a rock than its most likley its bad.

Is the CEL on??

I just bought a 2001, on the dealer lot it had an idle issue, it was a constant up/down on the idle. In fact, it would "rock" the entire vehicle forward and back.

Took it to my brother in law and he said it was possibly a idle air intake valve/motor... and sure enough, the dealer replaced it which is what I required to be done before I bought it.

So... wish me luck, just got it today. :)

Dealership ran the $98.00 diagnostic, could only get slight idle propblem, but nothing conclusive. They called "Ford" directly and was told this. Winter gas has additives per region ours is Illinois. Depending on how warm the weather is this additive doesn't burn completely and the fuel pumb will react causing the unstead idling.
Now that the days have been consistantly cooler I do agree. Moreover yesterday being in the high 40's I notice a slight idle problem again. It hasn't been enough time to fully test what "Ford" said but so far it stands to reason.
We didn't get charged $98.00 diagnostic charge.

I saw a news story about a lot of cars (many brands) showing up at dealerships needing fuel injectors cleaned in November.....The story stated that it started right when we switched to the "Winter Formula" for our gasoline.
We use the same formulation in the Milwaukee area as is used in the Chicago area. This formulation is used only in Southeast Wisconsin and the Chicago area.

It would be nice if the gas companies, clean air act and the automobile industry all had phones and could actually communicate.

I was told 3 yrs ago from dealership when van starting showing some irregular idling, that I should stay to a good gas. What is good gas. Well lets just say it's not at the most economically priced gas station. I've been using Amoco BP med. grade gas. However on odd times when I can't get to a BP or second best shell and am forced to buy speedway or the like I find idling problems. Don't know what that's all about but it's happened time and time again.