Idle - What to try next

[beau]

My 97 explorer SOHC v-6 had a very rough idle. At the suggestion of some of the guys on this board I tried to fix the idle by (i) replacing the IAC (didn't use new paper gasket - just reused old rubber one in there - possible mistake) and (ii) cleaning the MAF sensors (went fine). I also added a bottle of sea foam to the gas tank, but I couldn't get the vaccuum hose off of the master cylinder, so I didn't put any in the intake manifold. This stuff helped a little bit (I think) but the idle is still fairly rough. (Didn't see any loose hoses, but I probably wouldn't know enough to tell if one was entirely missing.)

Just bought it with 101K miles, so I have no idea what maintenance has been done. So... question is: What should I do next? New fuel filter? New plugs and wires? Take it in for the manifold gasket fix?

I guess this is kinda like a a doctor diagnosing a patient. (Hook for horses not zebras - most common problems) What's the next best bet for a fix after IAC and MAF?

I could take it into autozone and have it scanned. Would that help diagnose the problem? There are no lights on the dash, but could there still be a code that might help?

 

[Garth]

Wires and plugs should be priority. Did you check to see if they were ever changed? Owing that they can last up to 100,000miles some people dont bother looking at those.

 

[daniel cauchon]

try cleaning your TPS (Throttle position control) it must be it.

 

[daniel cauchon]

here is the answer to your prob

Just want to thanks you guys for helping me with this problem...it was the IAC...cleaned it and it runs as new now ! This site is very helpful to me ...2 prob up to now and 2 solutions that turn out to be right on ! very good average !!

 

[EBInterceptor]

Go back and run some Sea Foam through the intake. I ran it through both the intake and gas tank. My engine should vibrate rather roughly on and off when idling and sea foam fixed the problem. Getting the brake booster line off is kind of hard the first time. I just held the connection on the master cylinder and wiggled and pulled on the tube for a few minutes before it finally came off. Don't forget to move the tube clamp back of course.

 

[RickOTR]

As for using SeaFoam, just do what I did. Cut the brake booster hose in half then put a 3/8" tee with a 1/4" end on it. Take a six inch long 1/4" hose and place it into the can of SeaFoam after you start the engine, and watch it go to work. After your done, just cap the 1/4" end of the tee. I now use the 1/4" fitting for my vacuum gauge inside the X to monitor the engine. I also noticed a drastic improvement in performance and idle.

 

[beau]

Thanks for the responses.

I replaced the IAC control. Very easy even for me, but that wasn't it.

I called the dealership and found out that they have the service records going back to '99. Apparently the guy who had the car before me did all his service there. After talking with the service advisor I decided to have the dealer change the plugs and wires for me. After 100,000 miles it probably needs it. They are going to charge me $250, but they are going to give me all the old service records too, and that's worth a lot to me (since I won't waste money on recall fixes and other stuff that has already been done, and I'll know if stuff hasn't been done).

I'll also try the TPS fix if I can find directions and see if that helps if the plugs and wires don't fix it.

Will advise on results.

 

[Garth]

Any recalls that was not done Ford will send you notice as a new owner.

 

[TPLYNCH]

Beau, ask the dealer if the intake manifold o-rings were ever replaced. They go bad and cause rough idle, especially when the engine is cold. Ask them about Owner Notification Programs 01M01 and 00M12 and if the work covered was ever performed on the engine.

 

[beau]

Okay, will talk to the dealer about it in the morning. Thanks.

 

[beau]

WOOHOO, it's fixed!

New plugs was all it needed. Of course the dealer ended up charging me a grand total of $284.69 for it, because the had to "diagnose" the problem. But whatever, at least its fixed.

Also - and although those were the most expensive spark plugs in the world - I did get the vehicle maint. history going back to '99, when the second owner bought the car with 20K miles. Both the cam chain guide recall fix and the intake manifold gasket fix were done. Also there was some recall fix done to the throttle body. At least I bought some peace of mind.