1998 Ford Explorer V6 SOHC That Idles Rough Only Part of the Time

[oriolesfan29]

I have a 1998 Ford Explorer with a 4.0 SOHC that idles rough sometimes and than not others. I have sprayed it twice with amsoil powerfoam and it is still there. I don't know what else it could be. Maybe a sensor or vacumn hose? If anybody could help me with this I would appreciate it.

 

[lil_one71742]

I was having the same trouble with my car.. It started throwing codes so i scanned and figured out it was a oxygen sensor.. Its more than likely some type of oxygen sensor.. There are four on you truck... Is the check engine light coming on?

 

[Nocturnall]

Could also be a vacuum leak, does it idle rough when you first start it then it goes away when the trucks warm?

It could be the orings on the intake manifold which are known to go bad on the SOHC. Could be the IAC on the side of the intake manifold is dirty and needs cleaning. Start with cleaning the IAC if you don't have a CEL.

 

[oriolesfan29]

Thats just it, the check engine light doesn't come on. It does seem to do it more when it is first started but it does also do it sometimes when it is warmed up too.

 

[toypaseo]

My idle got better when I replaced the DPFE.

 

[Nocturnall]

Try cleaning the IAC it's a silver thing on the right side of the intake near the top. 2 8mm bolts that hold it on. There will be a lot of carbon build up on it, try cleaning all that off and see if it improves.

 

[Jeff00000168]

Have you ever tried replacing your TPS (Throttle Positioning Sensor)?
$20 at Auto Zone

Same thing happened to mine about 2 years ago. The check engine light never lit up but eventually did after 6 months. I replaced the TPS and idle was perfect. Even gear shifting will be smooth as a Lexus.

 

[oriolesfan29]

What is a DPFE and an IAC. Anyways, I am going to try to replace that TPS and see if that does it. My dad has a dakota and it had a problem somewhat similar to it and that sensor was the cause. Any other suggestions would be appreciated, I will let you know when I have put it on.

 

[Nocturnall]

IAC is idle air control. If you have a multi meter you can check the tps before just replacing it. I'm a cheapie I would clean the IAC first because it'll cost $0.50 in carb cleaner and 5mins with a brush.

 

[oriolesfan29]

Well, I took in what all of you guys said and it is still doing it. I replace the TPS and cleaned the IAC. Does anybody have any other suggestions.

 

[khibdwb]

Had the same problem with my 1998 Explorer.

Turned out that the problem was I had a snooty truck. Cheap 87 octane gas was not good enough for it...I had to give it the higher 89+ octane AND it had to be a specific brand...Holiday Station...(my brother who's a mechanic doesn't believe me).

The guys at Autozone said the computer code indicated a misfire. Did a compression check on all cylinders--all good. Changed plugs. Changed wires. Checked voltage resistance on coil--good.

Nothing helped.

Went back to mid-grade gas...everything's back to normal.

Go figure!