Rough Idle - 02 Explorer 4.0 XLS pre March Build

[delusive]

UPDATED w/Sensor Data:::Rough Idle - 02 Explorer 4.0 XLS pre March Build

My idle started getting rough, not dying, but coming close. Two days later the CEL came on. Advance showed bad O2 sensor bank 1 upstream. Next day, I had them check again after clearing CEL, now both upstream sensors. I searched on here and it seems there are multiple possibilites:
1. Air Filter
2. MAF
3. Throttle Body
4. IAC
5. Vacuum Leak
6. Fuel Filter
7. O2 sensors

Here is what I have done so far:
1. Replaced air filter
2. Cleaned MAF
3. Throttle body looks clean
4. This is where it gets strange. While the engine was off I pulled the hose from the intake to the brake booster. I then blew in cigar smoke to find possible leaks sites. Smoke was found coming out from somewhere around/under the throttle body. I hooked the hose back up, ran engine until warm and rough idle. Then I sprayed WD40 again all around where the smoke came from and...nothing. The idle never picked up. What does that mean exactly? I can't hear any noise like I have a vacuum leak either. I'm afraid to keep sinking money into this vehicle as it has 213k miles and the rear end is roaring like no other.

I am not a mechanic and have been winging it based on internet searches. I also have had 4x4 high flashing and bought new module for that (not yet installed). The door locks and keyless quit working also. Tried programming mode and it didn't work so bought a new security module also (not yet installed).

Any suggestions on what else to try or just get rid of it?

 

[swshawaii]

Were your DTC's p0171 & p0174 by chance?

http://www.explorerforum.com/forums/showthread.php?t=314670

 

[delusive]

Were your DTC's p0171 & p0174 by chance?

http://www.explorerforum.com/forums/showthread.php?t=314670

I've tried finding this elbow people talk about, but for the life of me I can't find it. Most pictures people post are from V8 engines, or another different model than mine. I've seen some posts mention it is between the intake and firewall, which if that is the case, I can't get to it.

 

[swshawaii]

If your 4.0 SOHC is the same, remove the throttle body cover first.
Move the upper radiator hose to the side as seen in the first picture.
RockAuto, O'Reilly, and Amazon all show the KCV-190 compatible on your '02.

 

[delusive]

If your 4.0 SOHC is the same, remove the throttle body cover first.
Move the upper radiator hose to the side as seen in the first picture.
RockAuto, O'Reilly, and Amazon all show the KCV-190 compatible on your '02.

Here is a pic of my engine, I think it is different than the one in your link.

 

[swshawaii]

Find a pic of a Motorcraft KCV-149 or a KCV-235, all I see were rep photos.
Use VIN to register, and search "Emission Control/Crankcase Ventilation System".
Hopefully someone will chime in and make your PCV elbow search easier. GL

http://www.fordparts.com/

 

[delusive]

Find a pic of a Motorcraft KCV-149 or a KCV-235, all I see were rep photos.
Use VIN to register, and search "Emission Control/Crankcase Ventilation System".
Hopefully someone will chime in and make your PCV elbow search easier. GL

http://www.fordparts.com/

Okay, the PCV and that elbow is on the back of my intake. I sprayed all over it and no change in idle.

I went back to my cigar trick. This time I removed the the tube that hooks the air filter to the throttle body, so that I could see better. It looked to me like the smoke was coming out near the intake bolts. Problem is, I spray all around there too and there is no change to the idle.

Could it be that the WD40 isn't doing the trick? Should I buy one of those little propane tanks and use it instead?

 

[swshawaii]

Starting fluid would probably work as well or better. Be careful, extremely volatile stuff.
The PCV elbow often splits or cracks on the bottom side and must be removed to check.
Did Advance give you any specific DTC p0 numbers? That would help isolate the issue.
Also, at 213K you are way overdue to change your PCV Valve if you haven't already.

 

[delusive]

Starting fluid would probably work as well or better. Be careful, extremely volatile stuff.
The PCV elbow often splits or cracks on the bottom side and must be removed to check.
Did Advance give you any specific DTC p0 numbers? That would help isolate the issue.
Also, at 213K you are way overdue to change your PCV Valve if you haven't already.

I haven't had the chance to mess with the explorer. I have a bad case of gout and can't walk right now. As soon as I can walk again, I plan to take it to Advance or Auto Zone and get the codes read again. I will write them down this time and post them here. I may also grab a propane torch and test for the vacuum leaks again with it as I believe I will see better results since it is a gas and not a liquid.

 

[dwatts2011]

I ordered the part mentioned here KCV - 129. I thought it was the , 90 degree elbow vacuum hose I needed. When it arrived it is 12 inches long. (KCV 240) Everything I look at says this has replaced the KCV 129! how can it be so hard to find a small 90 degree elbow... every part number on it has been replaced by this big piece. Does anyone know how I can get the part I need?

 

[delusive]

Starting fluid would probably work as well or better. Be careful, extremely volatile stuff.
The PCV elbow often splits or cracks on the bottom side and must be removed to check.
Did Advance give you any specific DTC p0 numbers? That would help isolate the issue.
Also, at 213K you are way overdue to change your PCV Valve if you haven't already.

The code since last clear has changed. It is now P1131. Now about this code, the person said it wasn't the standard code for the O2 lean. She said the computer didn't give the details for what that code normally issues and said to contact Ford because if it was the standard code that it would have given a description.

I bought a propane torch and will check again for vacuum leaks later today or tomorrow.

 

[delusive]

Update: I took the propane torch, attached a hose to it to reach the difficult places, and went to town on that engine. I could not find a single vacuum leak. I don't know why my smoke check showed a leak, but it must be a one way street because the propane doesn't get sucked in anywhere.

New symptom: I notices driving down the road that the engine does small stutters or surges occasionallly. At first I thought I hit rough road, and then it happened several more times.

SO, does the new symptom hint to something else. All that is left that I can think of is the IAC, Fuel Filter, or O2 Sensors. Is there any other possibilities? If not, which of the three listed should I tackle next?

Thanks for the help!

 

[home4sale2]

I personally don't think the propane or spray trick works or is reliable enough...it would have to be a pretty decent size hole in which case you would hear the whooshing sound. I can attest to it because I was all over the area where I eventually found the hole. Smoke method works better.

I specifically had P1131 and P1151. I replaced the intake gaskets and bolts (you can find my post). I also had a major leak which I fixed. There was another post which pointed to O2 sensors but in that case you should get additional codes. I would check for leaks first. If it's fuel filter, it should start to get noisy so if that's the case, maybe do that next. So, my order of action if I were you would be (assuming you have lots of noise and you have cleaned the IAC valve and it visually looks ok):

- Leaks
- Fuel filter
- O2
- IAC

Good luck. Been through it recently so feel your pain.

 

[delusive]

I personally don't think the propane or spray trick works or is reliable enough...it would have to be a pretty decent size hole in which case you would hear the whooshing sound. I can attest to it because I was all over the area where I eventually found the hole. Smoke method works better.

I specifically had P1131 and P1151. I replaced the intake gaskets and bolts (you can find my post). I also had a major leak which I fixed. There was another post which pointed to O2 sensors but in that case you should get additional codes. I would check for leaks first. If it's fuel filter, it should start to get noisy so if that's the case, maybe do that next. So, my order of action if I were you would be (assuming you have lots of noise and you have cleaned the IAC valve and it visually looks ok):

- Leaks
- Fuel filter
- O2
- IAC

Good luck. Been through it recently so feel your pain.

I have not cleaned the IAC. Should I try that next? It seems like an easy step to try.

 

[home4sale2]

I did, make sure your gasket in good shape when you put it back. In betwen diagnosing the problem, you may want to reset the codes. I did that to make sure that I was solving the most current problem (in the event you solve one problem but inadverdently create another).

 

[delusive]

I did, make sure your gasket in good shape when you put it back. In betwen diagnosing the problem, you may want to reset the codes. I did that to make sure that I was solving the most current problem (in the event you solve one problem but inadverdently create another).

I just took the IAC off and there is no gasket. I put in my VIN at fordparts and it doesnt show one either. You would think something like that would have a gasket.

Update: There were two little green looking gaskets that set in the throttle body. They looked fine to me.

I read that the computer needs to be reset after cleaning the IAC. Is there a way to do this without unhooking the battery? Last time I unhooked the battery the module that controls the door locks and key fobs went out. I just got that fixed and don't want to risk it going out again. I just ordered a CEL code reader that can clear CEL lights. Can it also reset the computer?

 

[home4sale2]

There is a gasket for the IAC valve so check that, at least on my 2002. There's no reason to reset the computer if you can clear the codes.

9F670
(CG-765)

Fuel Injection Idle Air Control Valve Gasket
4.0L V6 12V Single Over Head Cam EFI
$11.38
fordparts.com

 

[delusive]

Engine light came on again after cleaning IAC. I have my own code reader now and here is what I get specifically:

P1131 - Ford

Type
Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled

Description
Lack of HO2S Switches, Sensor at Lean Limit Conditions

Location
Bank 1 Sensor 1

Cause
Engine running in closed loop, then the PCM detected that the HO2S-11 signal did not switch because the fuel control system is at its lean limit

 

[delusive]

Current Fault Log
------------------
P1131: Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1

Pending Fault Log
------------------
P1132: Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 1

 

[delusive]

I have my new code reader and it reads some pretty detailed stuff using Torque on my droid phone. I recorded some of the data when I started having the idling issue. A little past half down the pic, my idle drops to 460. The voltage to Bank 1 Sensor 1 is at 0.19 where Bank 2 Sensor 1 is above 0.5 almost the entire time. Does that mean the sensor isn't working? Also there is a few times when the Vacuum reads 0, I don't know if this is really a loss of vacuum or a glitch in the program or lag. And lastly, the fuel trim is solid the entire time on Bank 1 with a postive number, where as on Bank 2 it is always changing and a negative number. Can anyone make sense of this info: