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2005 Explorer 4.0 SOHC - Engine Shake at Idle

10K views 4 replies 3 participants last post by  J-ward61 
#1 ·
Good afternoon,

Over the last month 1/2 I have been dealing with the "rough engine/shake at idle" issue that many others on here have posted about. I bought this 2005 Explorer from my aunt after my uncle passed last October. It has 118,000 on it now. I want to layout what I have all done thus far and then see if anyone has any ideas moving forward to get this resolved.

1. Replaced Air Filter
2. Cleaned the MAF (also ran truck with it unplugged and the issue was there, just a little worse.
3. Cleaned the throttle body until it looked like a new one.
4. Plugs and wires
5. Fuel Filter

After all of these things (which had never been done so they all really needed to be done anyways) I was still having this issue. Then I found the post about having Ford flash the ECU with an update. Thinking this might fix it I went ahead and had that done. It did bring the idle up to around 700-740 (it was at 600-615 previously) it didn't fix the engine shake at idle, and actually made the shake even more noticeable.

6. Flash ECU

Finally I took the Ex to a very reputable shop that I have had alot of other work done at. They proceeded to diagnose the problem like I hadn't done anything yet. Once they got to the smoke test I admit I was hoping this would be where we figured it out, but they couldn't find any leaks anywhere, except from the EGR valve which they mentioned is somewhat normal, but he would continue checking. After looking at fuel trims and everything else (one of the banks was running a bit lean) he tested the EGR valve from the tool. He would slowly open it up 10% at a time at idle, watching to see if the value changed. It didn't change until 50%, which is where the engine really started to run rough. He was fairly confident that it was the EGR that was causing the issue, so much so that he said he wouldn't charge me for the 3 hour diagnosis if that didn't fix it. Well 2 days later I replaced the EGR valve and no change at all!

7. EGR Valve

So this brings me to where I am now. I have no idea where to go next and am sick of throwing parts at it (even though most of the items above needed to be done).

I am hoping someone on here can point me in the right direction to fix this issue!

Thanks,
Curt
 
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#2 · (Edited)
Could be your IAC, idle air control valve. If the SOHC hasn't changed where IAC is between 2000 and 2005, it's on the top middle nearer the firewall, right under the plastic shroud.

When mine got too dirty I successfully cleaned it, spraying in carb (or throttle body) cleaner and swabbing around with a cotton swab, working the actuator shaft up and down too. Also take the plastic cap off the side if so equipped, spray carb cleaner down into that shaft and also take the two felt filters out of the cap and clean them with carb cleaner too.

Once clean I shook out excess cleaner, let it dry, then stood it up on end and put a drop of 5W30 oil on the actuator shaft where it meets the bronze bushing and worked the shaft up and down a few times to work the oil into the bushing, then left it propped up so gravity would continue to work the oil down into the busing for several hours.

When reinstalling, make sure both mating surfaces are clean. If you have the silicon o-rings type gasket on the engine you don't need a paper gasket. If you don't then you need a paper gasket. If you want to reuse an existing paper gasket (if it didn't rip while taking it off) then I'd consider putting a tiny bit of RTV sealant on it, though I think you can get those gaskets from Rockauto, or just buy bulk gasket material from a local auto parts store and cut your own... but you probably have the silicone gasket and don't need to.

Some people have cleaned theirs and it wasn't enough, they ended up having to replace it. Mine is still going fine more than a year after the last cleaning but I think not everyone oiled theirs and the drop of oil is important to get the bushing lubricated again so the shaft doesn't seize in it.
 
#3 ·
I thought that since this is "drive by wire" that there is no way to clean the IAC as it is part of the throttle body, and I have already cleaned the throttle body. It is all computer controlled (IAC) so there really isn't anything to clean. If I am wrong please correct me because I will try just about anything to get this vehicle idling normal.
 
#4 · (Edited)
Yes I think you're right, didn't realize they changed to drive by wire in 2004 forward.

Are there any OBDII trouble codes set? Did any of the spark plugs look different than the rest or especially dirty? Had the vehicle sat for a long period with the same tank of gas so it may have gummed up the fuel system? I assume you have ran through at least the tank of gas it came with and are using fresh fuel now?

If a cylinder is running lean I would check the fuel rail pressure and wonder about that cylinder's fuel injector, if all else fails I'd pull the fuel rail and swap that injector with another to see if the lean condition follows the injector, though once you pull the rail you'll want new injector o-rings for all of them. Maybe first try a fuel system cleaning solution, Techron or similar.

Another thing to try on that lean cylinder is a compression or leak down test, though to be thorough you ought to test all cylinders while you're at it.

Beyond these things, I'd try to make as detailed a list as possible of what the shop tried and take it to another shop to go from there. Spending 3 hours they must have tried more than mentioned, for example I would think they ruled out a bad ignition coil but who knows?

Then again, throwing parts at it by DIY isn't always a bad option if you're getting charged for labor at a shop and end up with a lot of things you can not only rule out but that should be working well into the future.
 
#5 ·
if your still having the issue try changing your spark plugs with ford oem plugs...mine was doing something similar and was suggested to try that even though I had just changed the plugs not long before....and it fixed it...apparently some makes are picky with their plugs....I work at a vw dealer and they are the same way...doesn't seem to matter if its the same brand as oe (i.e ngk or whatever)
 
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