Windstar intermittant rough idle

I have a Windstar '98, 168.000 miles, 3.8. It has started to idle very roughly, but the problem is very intermittant. It seems to only occur when sitting in traffic, idling, in gear for over 5 minutes. The check
engine light does not come on, even when it is obviously misfiring.
I had the computer scanned and no codes were stored. I'm a little confused, as I thought the computer would pick up any type of misfire, so it could be diagnosed. I was hoping it would at least tell me which cylinder had the problem! Any ideas as to why the computer does not give me any informaiton?
I talked to the dealership mechanic and and he suggested I start by replacing all the fuel injectors. He said as the FI ages, the resistance goes up when the FI gets warm/hot and are a very common cause of intermittant misfire, especially in the conditions I describe where the under hood temperature goes up from stop and go traffic.
He also told me 150K is beyond the service expectation of a ford fuel injector. He also recommended buy the full set of FIs, as they are usually within 3% of each other for fuel flow. As if you buy them one by one the fuel flow could vey by as much as 15%.
This sound like an expensive fix for guessing what the issue is. Any suggestions?
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Did a little more diagnosing and here is what I found.
After warmed up, if I turn on the headlights and blower, one of the fuel injector just stops working. With my voltmeter, it showed 12.0 volts and it stopped working, 12.5 volts and it was fine. Never would have guessed that the voltage dropping half a volt would be the difference between a FI working and not working!
Lucky it was one front middle, so two bolts and 10 minutes had the new one in. Time for a test drive!!
Still debating if I should replace all the FIs, or just wait for them to die one by one.
It it normal to have a FI die a slow death like this?

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I had a fuel injector problem that turned out to be a bad contact in the connector. Over time, corrosion created a resistance that affected operation of the injector.
Of course, this means that the problem was intermittent. That only adds to the fun.
Ken
Jack wrote:

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Jack wrote:

All guessing is expensive ... and a gamble ... just look at that last piece of shit for a President we got killing our troops for WMDs, mushroom clouds and imminent threats.
So ya wanna slam dunk this ... it is more likely to be a fuel problem then electrical or air pressure (smog control) as that would tend to be more persistent ... it runs rough all the time sort of thing.
I am guessing you have a fuel delivery problem before it get distributed to the injectors ... seems it is all the injectors that are suffering or starving when it runs rough and then gets better.
If your fuel filter is good, and dunno if this is an electrical fuel pump, if so then that might be going out if it is original equipment and that is what I would think about fixing up a bit.
If you have a mechanical fuel pump that works off the engine torq, then same thing might be going on in a different way.
Short of this .. have to wait until it is smoking or on fire or does it all the time, run rough .. then you will know what is broken.
sumbuddie hopes this helps
:?
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