'00 4.0 sohc running rough

[Yooper detective]

Hey, guys:

2000 Ford Explorer 2wd 4 liter, believe the rebuilt engine has about 170k on it. The body has 320k on it and the transmission, replaced 50k ago, was a used unit with 57k on it. I drive about 60k a year in varied weather. The check engine lightbulb itself has been burned out for at least 50k. So no clue if it's still on (a pretty good bet) or if it's blinking out "FOR DEAR GOD JUMP OUT OF THIS TRUCK AND RUN AWAY RIGHT NOW" in Morse Code. I'm thinking the lightbulb may be in panic mode and the bulb itself actually fled the vehicle to save itself.

But...

A couple of recent problems have led to an operating issue. For starters, I replaced the radiator and after this the fluid level kept dropping. I had it overheat once and fluid was actually being expelled from the reservoir bottle under pressure, so assuming there is a head gasket issue somewhere, but it operated all right.

Yesterday I drove 60 miles and noticed a little chugging toward the end of the trip. Then I drove around in that area and every time I started the vehicle it chugged and ran rough, and it ran rough when I was rolling at a steady speed, but it accelerated smoothly and with power.

On the trip home, with cruise on, it ran rough but the severity came and went. Mostly smooth driving. I had to climb a couple of hills and it seemed to have power one time and no power the next time. Whatever the problem is, it's been intermittent at best.

I checked fluids and there's no curdled milk in my oil. Just checked the antifreeze, which was full yesterday, and now it's a quart down, which is about what it does every time I run it for more than 100 miles.

It's outside idling right now and occasionally lets out a popping sound from the exhaust, which is cracked above the muffler.

Sounds like fun.

Anyone have any ideas?

I'm personally hoping bad gas and a weeping leak somewhere that's not related to a head gasket. Going to get the fuel filter changed (150k since it was changed, at least) and crossing my fingers.

Again, any ideas?

Yooper Detective
Yes, I'll drive this until it dies

 

[Yooper detective]

Update

Had a mechanic drive it and he thought a plug was fouled, possibly by leaking antifreeze from a cracked head or head gasket. He recommended replacing all the plugs, look for a fouled one, then replace that one if it starts acting up again.

I short changed that deal. We ran the codes and found that plug 6 was misfiring. I replaced plug 6 and have driven about 10 miles without a burp.

I'll update after a few hundred miles driving tomorrow.

Anyone see any problems with this? The ONLY thing I've done to the engine was remove the wire and plug and put in a new plug, plus spray that dry wire over the wire.

We'll see how it goes.

I guess the other question is does it benefit anyone or hurt anyone to replace ONE plug. I know ACDelco doesn't agree with this theory, but is there an issue?

Yooper dude

 

[marragtop]

How long since all the plugs and wires have been changed? If it's been more that 50k, you might want to consider changing the wires and plugs. Also, it could be that the wire is bad which would foul the plug. If so, the new plug will foul eventually. Congrats on the overall 320k miles!! Is that the SOHC or OHV motor?

 

[joat]

water low i bet i know why

i just tore 2 explorers down last week a 99 and a 98 4.0 cast iron heads both used water but not a lot to worry about both kept fouling plugs tore them both down and the heads on both were cracked between the valves not a bad days work but its most likey your problem

 

[Yooper detective]

Update

It's an SOHC.

Yeah, as to the head, I think it's cracked. All the mechanics I talked to said they expected it.

The other issue that came up was intake gaskets, but the mechanic who called out the bad plug said that's not my problem. But he said he sees a string of bad intake gaskets when the weather gets cold. He noted that the vehicle does not want to even idle when the intake gasket goes.

No idea on the last time the plugs and wires were replaced. It has been running well within acceptable norms for me so I haven't wanted to dump the cash/hours into doing the plugs. Also a bit worried about snapping one off or screwing up the threading. If it ain't broke, don't fix it, I say.

Ran to Wal-Mart and back and it's running fine. I look forward to replacing number 6 plug in a few months.

Further comments appreciated.

Yooper dude