intermittent engine idle

Hello Again,

Just an update to my 96 GL problem. At first I had the check engine light, codes indicated a misfire and running lean. Replaced plugs,wires and fuel filter. No misfire, but engine light on again. Points to O2 sensors as faulty. trying to get it scanned, but very busy lately. Yesterday the idling started to act up, whereby when you are stopped,parked or just slowly moving, the idling begins to jump and sometimes stalls. I replaced the battery as it was definately bad, hoping that the lack of power caused the PCM to lose its setting from time to time, thus resulting in the idling problem. Still has poor idle. When the RPM's are above 750, runs smoothly, but anything under that, then it starts to bounce and stall. Any suggestions as what to check next. PCV valve?EGR Ports? What should the idling setting be when just parked?As far as I can tell no vacuum leaks according to the mechanic.Would like to do it myself if at all possible.

Thanks
Dion

1st step would be to get the codes scanned....and make sure that you get the actual numeric codes.

As with most any modern car, vaccum leaks will drive you crazy until you track them down. Often O2 sensors are replaced when it was a vaccum problem. Also...the Intake Manifold Runner Control (IMRC) can cause problems....but there are specific codes for this.

Idle speed is controled by the Idle Air Control (IAC) which is on top of the upper intake manifold...right next to the throttle body. It is held in place by 2 bolts....and has an electrical connector. Very easy to replace...not real expensive..Can "stick".....Many have corrected IAC sticking by some WD40.

1st step would be to get the codes scanned....and make sure that you get the actual numeric codes.

As with most any modern car, vaccum leaks will drive you crazy until you track them down. Often O2 sensors are replaced when it was a vaccum problem. Also...the Intake Manifold Runner Control (IMRC) can cause problems....but there are specific codes for this.

Idle speed is controled by the Idle Air Control (IAC) which is on top of the upper intake manifold...right next to the throttle body. It is held in place by 2 bolts....and has an electrical connector. Very easy to replace...not real expensive..Can "stick".....Many have corrected IAC sticking by some WD40.

I'm trying to get in contact with the mechanic to get the codes read.Unfortunately here in Canada( at least my area) there are no places to get the codes read for free.I was told that the O2 sensors appear to be the fault, but somehow I don't think so. And as far as I was told, no leaks.For some reason I think its the EGR Ports, but I'm not a mechanic so its just a guess.
Is this IAC part of the vacuum system? How can I check it?

Thanks
Pryornfld

I have a 2000 Windstar and am having basically the same problem. I have replaced all 4 O2 sensors, fuel pump, spark plugs, air filter, PCV valve, and the Throttle Positioning Sensor. I am down to possible vaccum leak, or fuel injector problem. I ran the test and came back with P01121, P0171, and P0174. TPS problem, and lean fuel mixture on banks 1 and 2. respectivley. Any help would be appreciated

Still haven't gotten the codes read. Turns out the entire family decided to get sick, thus spent alot of time at home. Hope to do it sometime this week. Anyway, it was -23 deg this morning and when I went to start the van, it cranked like it should, but it wouldn't hold its idle. I had to keep my foot on the gas for about 30 sec until it was able to hold its own idle. Any clues or hints out there???

danstrait
I would suggest focusing on the P0171, P0174 codes --air leaks after the MAF sensor. Make sure your air filter cannister is not the problem before attacking the intake manifold. Even the seal around the sensor itself can be leaky. I like to use petroleum jelly on all these joints to help sealing.

Should have included in my last post, but I want to plug in my block heater, but the plug was torn off. Is there any special polarity I should worry about when connecting a new plug? If anyone has a wiring diagram, please let me know.

Thanks
Pryornfld

I'm trying to get in contact with the mechanic to get the codes read.Unfortunately here in Canada( at least my area) there are no places to get the codes read for free.I was told that the O2 sensors appear to be the fault, but somehow I don't think so. And as far as I was told, no leaks.For some reason I think its the EGR Ports, but I'm not a mechanic so its just a guess.
Is this IAC part of the vacuum system? How can I check it?

Thanks
Pryornfld

I too am from Canada and I ended up buying a code reader for the same reason that you mentioned. We have nowhere to get them read for free. You can purchase a code reader from Canadian tire for under $200. I think it will pay for itself over and over again especially when you consider that it costs $50 to have the codes read minimum.

I read this thread and I think many have given you some good starting points but you may wish to also add the EGR as a possibility too.

I think knowing the codes is the starting point.