Hey guys any idea on what's causing my idle problem?
Not a big deal but it should be smooth.
Here's the scenario.
10K miles.4.0 L
Start up it's idles fine.
Then after say 10 seconds she idles a bit rough,then smooths out,then seconds later idle a bit rough again.
A bit rough.
Not bad but still not right.
Any ideas?

 

i have a 05 with same thing only 500 miles . dealer said it was normal because of the cams. dont know if thats true . they also reprogramed the computer cause they said there was so new software.

 

You have the problem too.
Interesting.
I just bought the truck a few weeks ago from a Ford dealer.
I thought maybe a 20 ounce Techron fuel injector cleaner would help but it didn't.

I don't buy the normal B.S. service advisors answer to a problem.
I'll see if I can find a TSB.

 

I have 05 4.0L with 3250 miles and it does the same for me. It doesn't seem to effect anything.

 

I found out there is a tsb on this problem.
TSB 04-21-12
Rough Idle


Issue
Some '04-'05 Explorer/Mountaineers built before 10/04/2004 with a 4.0L may exhibit a rough idle/vibration at base idle and trans in drive.
This condition may also be described as an intermittent shake or bobble at idle.


Action
Reprogram powertrain module to the latest calibrations using WDS B33.10 or higher.
Calibrations files may also be obtained at website.

Check for Diagnostic trouble codes and reprogram powertrain module 0.4 Hrs labor.


My Explorer has a slight rough idle.
Not a big deal but will let Ford check it out when something else goes wrong.
Until then I can live with it.

 

Just got the truck back from the dealer.
The PCM was reprogrammed.
90% improvement.
A little twitch here and there but much better than before.

 

There really shouldn't be much variation at all at idle. It's not like Ford is going to program a little richer, a little leaner, a little richer, a little leaner...either over time after start up or in relation to engine temp or any other sensors. There should be a linear curve of the A/F ratio over certain conditions. Cold start runs rich and holds idle at 1,200 R's, then drop to 1,000 R's, then 800...and also in response to engine temp but always linear. As engine warms up, A/F goes leaner.

I even had a TSB back in 95 for my 93 Explorer - change PCM to a 94 unit with rich cold start table. So this type of updating the computers for idle problems is not new. But the update should have fixed the problem in its entirety.

If you stil have concerns, it's likely an actuator is not doing what the PCM says. Like the IAC may be bad and not controling idle correctly. I've even heard of relatively new DPFE EGR sensors being bad causing idle problems. If they report back more or less actiula EGR fuel, the PCM can't send the right amount of fuel to the motor - rough idle. Then the O2's fight back...kind of an endless cycle.

If it's still showing issues, don't live with it. Make Ford fix it.

 

Interesting,thanks.
It's under warranty so I'll continue to monitor the problem.
Although it's a very slight difference at times.

 

I have the same problem on my '04 Explorer XLT. I had the PCM reprogrammed about a month and a half ago and it made a difference but not too much. The idle is shaky in park but when in drive it smooths out a lot more with a slight stumble here and there.

 

Same problem here. 05 with 6k now and it has idled rough from day one. Had to have the tensioner pulley replaced already but the rough idle remains. I'm about to bring it in again and want to be as armed as possible.

 

Idle issue was back this morning.