Performance issues with my 1998 Explorer.

[Austin Johnson]

Hey, I'll start off by saying, I'm Austin, I own a 1998 Ford Explorer aka Exploder! It has 223,0000 on it and it's the OVH 4.0 v6!
Now my first problem is a rough idle that has killed the engine three times (yesterday) When I was driving it, it ran fine, and then when I got to my fire department, I left it running, about 2 minutes later it bogged down andashut off! This truck has always sounded like it was skipping or misfiring, but it was so light, you could barley tell, sometimes it will vibrate in the truck, but again you couldn't tell sometimes it idled fine other times it idles rougher! But now that it's shutting off, I'm concerned, I bought this truck less than a month ago. And I'm actually a Dodge guy, but I liked this truck for the price, so when I heard it sounding like it was skipping and or misfiring, I thought for miles and age maybe that's just how it sounded, now I know there is something wrong. And I cranked it this morning, and it's running good! Again when driving down the road she runs good!!! And there is no check engine light!!! Any help would be great!!!!! Thanks in advance!!!

 

[BrooklynBay]

Welcome to this forum! When was the last time the plugs & cables were replaced?

 

[Austin Johnson]

Welcome to this forum! When was the last time the plugs & cables were replaced?

Well according to the owner about 6 months ago, and I believe him because the plugs still look nrw

 

[BrooklynBay]

Do you know what kind of plugs they are? I've tried Bosch Platinum, and the engine had no power. Use Autolite or Motorcraft platinum plugs.

 

[Austin Johnson]

Do you know what kind of plugs they are? I've tried Bosch Platinum, and the engine had no power. Use Autolite or Motorcraft platinum plugs.

No I have no clue, When I get a minute illI look and see

 

[BrooklynBay]

Both of your threads were merged, renamed, and moved into the stock 1995 - 2001 Explorer section. Check the battery terminals for corrosion, the PCM ground wire, and the PCM/fuel pump relay. Do you see the check engine light illuminate when you turn the key? Does the fuel pump prime?

 

[Austin Johnson]

Both of your threads were merged, renamed, and moved into the stock 1995 - 2001 Explorer section. Check the battery terminals for corrosion, the PCM ground wire, and the PCM/fuel pump relay. Do you see the check engine light illuminate when you turn the key? Does the fuel pump prime?

Yes my check engine light comes bon when I turn the key, the battery terminals are in good shape, and yes the fuel pump primes

 

[Austin Johnson]

Yes my check engine light comes bon when I turn the key, the battery terminals are in good shape, and yes the fuel pump primes

And I don't know much on how to work this website, I'm new here, like today new

 

[sidneyhop]

Could this be the intake manifold gasket? I know the v6's had a recall on this issue.
On a side note. V8 Gen 2 Explorers are built like tanks, V6's not so much.

 

[koda2000]

I don't want to scare you, but one of the more common problems the 4.0L OHV V6 is that it suffers with cracked heads. Other than that it's a very reliable engine and will pretty much run forever. Determining if you have a cracked head can be difficult, as the cracks typically occur between the valve seats and can close once the engine heats up. Also, look for bubbles in the radiator coolant and monitor your coolant level closely.

A common first fix for these tiny head cracks is try putting a bottle of product called K-Seal into the cooling system (I prefer to add it directly to the radiator). For many this has sealed the crack and no further repair has been necessary. It might be worth a shot and will not hurt anything. Cost is around $12-$14 depending where you buy it.

Even it it turns out that you have a cracked head, it's fairly easy (and not extremely expensive) to replace a head on an OHV engine.

 

[fast_dave]

Hey, I'll start off by saying, I'm Austin, I own a 1998 Ford Explorer aka Exploder! It has 223,0000 on it and it's the OVH 4.0 v6!
Now my first problem is a rough idle that has killed the engine three times (yesterday) When I was driving it, it ran fine, and then when I got to my fire department, I left it running, about 2 minutes later it bogged down andashut off! This truck has always sounded like it was skipping or misfiring, but it was so light, you could barley tell, sometimes it will vibrate in the truck, but again you couldn't tell sometimes it idled fine other times it idles rougher! But now that it's shutting off, I'm concerned, I bought this truck less than a month ago. And I'm actually a Dodge guy, but I liked this truck for the price, so when I heard it sounding like it was skipping and or misfiring, I thought for miles and age maybe that's just how it sounded, now I know there is something wrong. And I cranked it this morning, and it's running good! Again when driving down the road she runs good!!! And there is no check engine light!!! Any help would be great!!!!! Thanks in advance!!!

@Austin Johnson,

Idle problems on a 4.0 OHV - here's the basics.

The IAC Valve (Idle Air Control Valve) controls the idle function - via communication with the ECU (Computer) - and frequently on the OHV the IAC needs cleaning or outright replacement. In short, it gets gummed up with carbon and soot.

It's placement on the side of the black plastic intake is such that it sucks fumes from the PCV System, thus the soot and carbon.

Another indication that the IAC it's at the cleaning stage is that when the engine is running, and you let the hood down slam shut, and the idle speed changes (lower) it needs cleaning.

NOTE: If the black plastic filter is still attached to your IAC, you can try pulling that off and seeing if your idle improves - frequently that filter is plugged with fine grain sand/dirt.This will cause a rolling idle at stop lights.

Use the search function to find one of the many articles of how to clean the IAC valve.

Do you have 5 minutes of time? All you have to do is unplug the wire harness, and then remove the (2) 10mm bolts holding it in. Simple ;-)

At the same time as you clean your IAC Valve, it doesn't hurt to clean your MAF (Mass Air Flow sensor) with APPROVED MAF Cleaner. A dirty MAF can cause idle issues that include rolling idle, rough idle, poor gas milage, pinging

After cleaning both the IAC and the MAF, reset the computer so as to establish new idle parameters - this is VERY important.

20 Minutes of your time and a $7 can of MAF Cleaner - can it get any easier?

Everything I listed are very popular subjects that have been well documented many times over on this forum.

Hope that helps and your mileage may vary.

IAC Valve Picture: Standard Motor Products AC290, available at Rock Auto

 

[410Fortune]

Koda said it, exactly what I started thinking when reading your first post:
OHV + Intermittent miss, runs great and starts to miss, then progressively worse, then finally shut down
Sounds like a water leak that has been "treated" and now the leak is getting worse, water into the combustion chamber through a head gasket or head crack.

Welcome to EF Austin! We love these 4.0L OHV engines and the trucks around them here

Before we go straight to a head gasket problem, you should check your fuel pressure, especially when the truck gets hot and shuts off. A fuel pump getting older can do this too.....works great when cold.....then starts to lose pressure until it can't keep up demand anymore, sputter sputter, die.
Let it cool off....runs great again.

Also any check engine light?
We will want the codes if you do have one on when running

For the head gasket possibility:
Is it using any coolant?
Do you smell coolant when shes missing and stumbling, then shutdown?
You can look for external head gasket leaks with a flashlight, look for white/green seepage on the sides of the engine block

 

[EB4X]

I'll throw in my 2 cents....thoroughly spray throttle body intake with carb/throttle cleaner....and when you take off air-intake tube to access T.B. check end of tube/connection point....my 4.0 on Ranger was starting to deteriorate and make poor connection....and had these symptoms....

 

[lobo411]

Check to see if the plugs are wired in the correct firing order.

 

[Austin Johnson]

I don't want to scare you, but one of the more common problems the 4.0L OHV V6 is that it suffers with cracked heads. Other than that it's a very reliable engine and will pretty much run forever. Determining if you have a cracked head can be difficult, as the cracks typically occur between the valve seats and can close once the engine heats up. Also, look for bubbles in the radiator coolant and monitor your coolant level closely.

A common first fix for these tiny head cracks is try putting a bottle of product called K-Seal into the cooling system (I prefer to add it directly to the radiator). For many this has sealed the crack and no further repair has been necessary. It might be worth a shot and will not hurt anything. Cost is around $12-$14 depending where you buy it.

Even it it turns out that you have a cracked head, it's fairly easy (and not extremely expensive) to replace a head on an OHV engine.

Okay, but if it's cracked wouldn't it over heat??

 

[koda2000]

Okay, but if it's cracked wouldn't it over heat??

Not necessarily. These are typically tiny cracks between the valve seats.