2000 Explorer XLS, V6 Rough Idle, Multiple Codes

[EB4X]

/\ I've never had the BOTTOM intake off...so not familiar with all that....but that appears to be normal, in fact necessary so you don't have any rear leaks back there....seems the "goal" is to have that whole rear section of intake with nice layer of RTV. Apparently those are water jackets/ports coming up from block and just "end" there at lower intake. See 8:00 minute mark of this video with Mazda (Ford 4.0 ohv engine) :
And then last pic of this ebay listing:

52k002 Lower Intake Manifold Plenum 2000 Ford Explorer 4.0 96TF9424AB for sale online | eBay

Find many great new & used options and get the best deals for 52k002 Lower Intake Manifold Plenum 2000 Ford Explorer 4.0 96TF9424AB at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[delicreepp]

The lower gasket was originally the 1-piece deal, and someone obviously went a little wild with the silicone gasket in the back. I have the two-piece fel-pro only requires extra gasket application across the bridges in the back and front. The instructions say to only torque all the gaskets to 12 ft lbs, so I assume I go with that.

 

[delicreepp]

Everything has been bolted down, reconnected, refilled and inspected (and re-inspected). Since I didn't get all the the gaskets done until 10am yesterday, I have not started the car while waiting the 24 hours for the RTV to cure. I did turn the ignition to ON after reconnecting the battery and nothing immediately caught fire. I'll be starting the car right after getting home from work later today.

 

[delicreepp]

The car started fine, and there are no leaks that I can see. Unfortunately, after one full day of driving, the engine light came on: P0401. I cannot seem to get rid of that code! I'm going to do some more driving today to be sure that the lean codes are gone.

 

[EB4X]

I put a cheapo ebay chinese DPFE sensor on rig, it cleared the code for about 2 weeks and then it came back, I then put on an old oem DPFE from Explorer at junk yard and code disappeared FOR GOOD! What brand of DPFE sensor did you put on?

 

[delicreepp]

I put a cheapo ebay chinese DPFE sensor on rig, it cleared the code for about 2 weeks and then it came back, I then put on an old oem DPFE from Explorer at junk yard and code disappeared FOR GOOD! What brand of DPFE sensor did you put on?

Standard Motor Parts.

 

[410Fortune]

That is typical of a blocked coolant passage, meaning look at your head, there is no port for coolant to flow from the lower intake into the head, it is a dead end right there and this “gunk” Always builds up at those dead end spots


The earlier 4.0 ohv the coolant flowed all the way through the heads in one direction, later ford changed the gaskets and forced the coolant to flow a different way, probably ending some dead spots and getting better cooling performance. So it is important to use the correct gaskets for your year of engine

Ford determines which way the coolant flows through the heads by blocking one or more ports off at the head. The 4.0 heads are symmetrical this is why the gaskets and ports are the way they are

Nothing out of the normal here. And like you I use a vacuum and compressed air to make sure none of that crap ends up falling back into the engine

 

[delicreepp]

The saga continues. Since our kitchen remodel was winding down (and a smog check was a month overdue--still need those tags!) I decided I needed to tackle that pesky p0401 code. The first thing I did was toss the cheapo DPFF sensor and replace it with one from Motorcraft. No change in the slightly rough idle, and the engine light came back on, still showing the p0401. About a week or two later, the idle became noticeably rougher. I replaced the fuel filter (something I had been sitting on since last May). No change. A quick scan showed that I now also had a misfire on cylinder 4. The spark plug looked fine, so I fine-tuned the gap and re-installed it. After that, I decided to go back through my repair purchases and found that I, in fact, did *not* install plugs recommended for my Explorer last May: Autolite XP104 instead of the 103's. I removed the Autolite plugs this weekend, switching to the Motorcraft SP500's. I also was determined to check the EGR line for leaks.

Now, I can hear those in the know muttering that I should be careful not to twist the line trying to free it from the manifold. Sage advice (as is"don't mess with it unless you REALLY have to"). I *was* careful: soaked it with PB Blaster, let it sit a good while before tapping and applying more Blaster, and then letting THAT sit for an hour or so. And, yet, I managed to twist it like a Twizzler. Got the new one on without much fuss and, of course, the old one didn't show any clogging.

After all that...a smooth, steady idle. I've only driven the car for 10 or so miles, so I have a bit more to do before I can take it to be smogged. Here's hoping the light doesn't come back on!

 

[delicreepp]

So far, over 100 miles driven and no CE light. The engine still practically purrs (for a 25-year old vehicle, anyway). Passed smog last weekend.

So...now I can move on to replacing all four shocks and the front suspension. It never ends!