Start up Problems of 1997 SOHC

[awhughes]

What is the consensus with the start up ideling problems of the 1997 and newer SOHC Explorers. I have cleaned the MAS and throttle body, and the truck runs great after warm up. My problem is at "cold start up". At cold startup the engine races up to 2500 rpm and back down to about 500 rpm, it rumbles there, but never stalls. If I let it go it will eventually stabalize the idle. It takes about 2 to 3 minutes to do so.
Could this problem be the IAT sensor or the IAC sensor being fualty? I have'nt brought it in to the dealer, so I dont know of any fault codes. It is to my undestanding that with these symptoms, they may not show up as a fault codes anyway. Has anyone experienced this idle problem and resolved it with replacing the IAT or IAC? I called the local Ford dealership and they are out of both of these sensors.
With my explanation of the symptoms, the parts guy suggested the IAC sensor.This makes me wonder if this is a common problem with the Explorer. Any input would be appreciated.

 

[Robert]

Originally posted by awhughes

What is the consensus with the start up ideling problems of the 1997 and newer SOHC Explorers. I have cleaned the MAS and throttle body, and the truck runs great after warm up. My problem is at "cold start up". At cold startup the engine races up to 2500 rpm and back down to about 500 rpm, it rumbles there, but never stalls. If I let it go it will eventually stabalize the idle. It takes about 2 to 3 minutes to do so.
Could this problem be the IAT sensor or the IAC sensor being fualty? I have'nt brought it in to the dealer, so I dont know of any fault codes. It is to my undestanding that with these symptoms, they may not show up as a fault codes anyway. Has anyone experienced this idle problem and resolved it with replacing the IAT or IAC? I called the local Ford dealership and they are out of both of these sensors.
With my explanation of the symptoms, the parts guy suggested the IAC sensor.This makes me wonder if this is a common problem with the Explorer. Any input would be appreciated.

You need lower intake manifold o-rings. Ford will replace them at no charge under Owner Notification Program 00M12. Call 1(800)392-3673 (Ford Hotline) and give them your VIN. They will fax the information to the dealer of your choice, preventing any hassles with the dealership. Your warranty on the o-rings has been extended to 6 years/72K miles (unlimited miles through 4/01). It is very common on the SOHC V6 manufactured through 4/00. It usually shows up around 40K-60K miles. My '97 had it at 51K miles. Don't spend a dime on it until you see your dealer, otherwise you will be wasting your money.

 

[awhughes]

I had the work performed today to replace the lower intake manifold o-rings and cam tensioners "campaign 00M12". This is the 4th set of cam tensioners on this vehicle including the original set. The last set of tensioners did not rattle but was part of the campaign so they were replaced by default.

The real test for the o-rings will be tomorrow morning on the cold startup. We shall see if the rough idle has been eliminated. I have my doubts due to how it ideled today after warm up. Could be that the plastic manifold is cracked, if so how did that happen? I have already replaced one other broken/cracked plastic housing, the blend door assembly.

If not corrected, I will be back at the dealership with a "big puss" on, requesting the manager. If they cant fix it, I will offer them the truck in a buy back deal. See how far I get on that suggestion.

Also, they replced the throttle-body assembly today. It is the third one including the original. This is getting old.

 

[awhughes]

That repair yesterday fixed my cold startup problems. Truck did fine at cold startup. The engine went to about 1750 RPM and settled down at ~1000RPM very quickly. My aggravation is over. Thanks for the suggestion Robert.

 

[Nonoy]

Mine too. It's gone. What a good feeling when you dont hear that ratling noise and a very quite idle. Wheeewwww.