Updated w/Solution:Starts if rested stalls going in gear


This turned out to be the ECT [Engine Coolant Temperature] sensor, according to my Ford dealer service department which was reading -20 on a 40 degree day. For those of you experienced enough how long should it take to diagnose this? What is a fair charge in diagnostic hours? Also, how long would it take to fix? According to the Haynes manual you have to remove the upper intake manifold, but it also states that it might be accessible if the thermostat housing is removed. If this is the case, shouldn’t this be an easy repair?
I have a 1999 Ford Explorer 6 cyl SOHC - It will start ok, idle high for 20 sec and then stall. Once it stalls it will not start up easily again - just cranks and cranks. If I hold the pedal all the way down I can get it to start very rough and then I have to keep the idle up or it will stall. Once forced into gear it will not stall and has all the power I ask it for. But it idles too high and surges while slowing down around 20 MPH. I can rule out the IAC and MAF and EGR valve. It will always start right away after resting over night. Surge also happens in neutral idle when you pulse the trottle. It revs up and hangs there too long before slowing down again. It will also stall when I take it out of gear. It will rev up and then fall to a stall. There are no OBDII codes returned. By the way this all began rather suddenly – drove 10 miles to store one day, went in, came out, started car fine, it stalled, then would not easily start again – before which you would not know anything was wrong. Any Ideas?

Things I think it is not and why:
- Fuel pump - it never loses power once in gear.
- IAC - I tryed a new one
- MAF - I tryed a new one
- EGR - took it out tested valve and blocked pipe while running with no change.
- Vac Leak - because it is so hard to restart?

Things I think it might be and why:
- Vac Leak - high idle : no symtoms during open throttle.
- O2 sensor - I do not know if there were codes for the O2 because now the OBDII for O2 is not ready because I disconnected the battery. I believe however that there were no codes when the O2 was ready

Comments very welcome!

Do you
have the same problem?
Sunday, January 7th, 2007 AT 6:46 AM

2 Replies


Hey 99,
If your not getting any codes, then its a tough call on my end! I'm sure if you were able to view data stream on a scanner it would reveal a direction to go in. I'm assuming you don't have a scanner. Though those MAF's are a known issue, I'm reluctant to say change it as they are pretty pricey. I gotta recommend taking it to a trusted shop for an accurate diagnosis. Unless you can get me some data stream values that is. Sorry


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Sunday, January 7th, 2007 AT 6:57 AM
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Just a couple notes to add. Disconnecting the battery to clear the codes will further complicate rather than help. I don't see a correlation between the OBDII monitors and the O2. Also, I have run into bad MAF sensor that were "new". Actually they are usually remanufactured. May want to consider the dealer part on that one. DPFE sensors are also common on these.

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Saturday, January 20th, 2007 AT 5:52 PM

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