98 3.8l rough idle + stalling + blower = ?

Hi guys - first time posting, this is a great forum. I bought a '98 Windstar about a year ago and been having problems with rought idle and it has stalled a couple of times already. from what i've rad in this forum i beleive the problem might be a vacuum leak somewhere around the intake manifold or one of the vacuum hoses. It might also be a bad EGR valve or DPFE sensor or clogged EGR ports / fuel injectors. Last week i noticed that when i turn on the interior fan (blower) and set the temp. to cool the rough idle stop would stop and the van would run OK. I know that there is leak somewhere because when i accelerate i hear it clearly. My question now is; what is connection between the heater/fan and the rough idle. I need to have my inspection in about a month and help from you guys will be greatly appreciated.

Hi - couple things. Read the posts about cleaning the IAC (idle air control). In case you are unfamiliar, it is the cylindrical electronic component on top of the throttle body. Many, me included, have seen better idle by cleaning it. Secondly, regarding your A/C question: I think the powertrain control module is reacting to the known/anticipated load of the A/C compressor and is "kicking up" the idle a bit to compensate.

thanks for the reply busboy4. The IAC was the first thing i changed when the rough idle began, but i will check to see if it's dirty. i definetely hear the vacuum leak thought, but i just can't trace it. any suggestions on an easy way to locate this leak? i've used the rubber hose as the Stethoscope but i guess my hearing is not as good as it used to be. thanks again.

Its the temp controller that may be causing the confusion. The actuator(s) is(are) vacuum powered and may leak more in "warm" than "cold" position. I would try disconnecting and plugging the vacuum supply that feeds the cabin climate system ... until you get beyond the emission inspection.

Its the temp controller that may be causing the confusion. The actuator(s) is(are) vacuum powered and may leak more in "warm" than "cold" position. I would try disconnecting and plugging the vacuum supply that feeds the cabin climate system ... until you get beyond the emission inspection.


Am not positive on the '98, but on the '96 the temperature blend door is electric.

As for the vacuum leak, I don't know other than trial and error. I will say the connections to the intake manifold are out-of-sight on the back of the manifold. You can see them with a mirror and a light. Or for best access remove the cowl.

busboy4
Yep, I bet you're right. I assumed (always a mistake) the earlier models were more vacuum dependent.
... disconnecting the a/c-heat system still worth a try just to take the climate control vacuum doors, hoses, etc., out of the equation.

thanks for your replies guys. i will try the suggestions over the weekend (weather permitting).