1998 Ford Taurus high idle

JOHN DOE WNY

MEMBER
1998 FORD TAURUS
6 CYL
FWD
AUTOMATIC
138,000 MILES

My 98 ford Taurus with the DOHC V6 idles about 2200 rmp when I first start the car then after about 10 sec. Then it idles down to 1500 rpm for about 30 sec. Then it drops down to 900 rpm where it stays. If I put the car into drive at any time from these idles it drops to 900 rpm and idles fine. Once it has idled in drive I can put it back into park and it still idles fine at 900 rpm. This happens summer or winter, cold or warm start. Check engine light is on and the code is mass air sensor among other things listed as a possability but this doesn't seem to act like a mass air flow problem. Thanks.

7 Replies

RENAUDTN

MECHANIC
636 POSTS

What are the codes?

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Tuesday, November 11th, 2008 AT 10:45 AM

JOHN DOE WNY

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I didn't get the codes myself I went to a parts outlet to have them read. They told me that it showed both sides running lean and they told me when that shows up the book says mass air flow sensor as the number one reason for this. Fuel pressure and o2 sensors were 2nd and 3rd things to look at. But since the car runs fine other than the idle problem that the mass air flow sensor is what they would replace first. I can get the codes if you like. Thanks

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Thursday, November 13th, 2008 AT 2:41 PM

RENAUDTN

MECHANIC
636 POSTS

Okay, it seems that you're talking about P0171 and P0174.
It is true that in a lot of cases a MAF sensor is the culprit. What I would suggest you do before you pay someone to replace it, is to clean it first. It would be a waste of money if the MAF still works and just needs a little cleaning.
You can buy a can of electronic cleaner for $2, and spray some on the MAF. It is located either inside your air duct (the big black hard plastic hose that goes from your air filter housing to your throttle body), or inside the air filter housing. You could actually buy a Haynes manual for instance; it will show you where it is and how to do it.
Usually you have to spray the sensor with electronic cleaner and let is soaked for 10 minutes, then repeat the procedure.
By the way, do NOT touch the sensor or scrubb it; just spray it.
If cleaning or replacing the MAF fails to fix your problem, I would look for a vacuum leak on top of what the store told you.

Let me know how it works out for you

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Thursday, November 13th, 2008 AT 3:41 PM

JOHN DOE WNY

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Hi and thanks for the replys, I got some spray cleaner made just for mass air flow sensors. I cleaned the sensor just like you described and disconnected and reconnected the battery. When I started the car after I cleaned it the idle went down but went right back up after about 5 secs. Then the check engine light came back on. Again thanks for the advice.

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Sunday, November 16th, 2008 AT 1:30 PM

RENAUDTN

MECHANIC
636 POSTS

Okay, did you let the sensor dry before you started the car? (You want to wait like 20 minutes after you've sprayed it, so that the sensor can dry).
Also, you may not have disconnected the battery long enough (usually 5-10 minutes). Note: it's better to use a scan tool to delete codes.
Also, after you disconnect the battery and reconnect it, your car may be running a little rough for a few miles; this is normal.

Here is a list of things to do/check:
- I would check the fuel pressure just to make sure it is within specifications.
- your MAF sensor could be bad and need replacement (since cleaning it didn't work)
- a faulty DPFE sensor or faulty EGR valve could also be responsible for your engine to run lean. Have them checked.
-You could have a vacuum leak. Have someone to check for vacuum leaks.
-Your coolant sensor could be bad
-Your o2 sensor could be bad.

If you're not really sure how to troubleshoot the above, I would suggest you take it to a mechanic. If you rely only on what the part store tells you, you could end up spending a lot of money in new parts that may not fix the problem.
If you're a gambler, replace the MAF sensor and see if it fixes your problem (since it is the culprit in a lot of cases); but again I make no guarantee that it does.