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rough idle 4.0L SOHC

sicktight722

Greatest man alive
Hello, Some may know I just bought a 98 ford explorer sport 4x4. Its and auto with an 4.0L SOHC engine that has 125K miles on it. When I got it, it was idling really rough, from the stock tach seemed to be close to 600 rpms. I pulled codes and got
P0304 (Cyl 4 Misfire Detected)
P0305 (Cyl 5 Misfire Detected)
P0171 (System Too Lean-Bank 1)

Well I cleaned the MAF, Cleaned the IAC, and put in new spark plugs and wires. I Then erased the codes and and took it for a drive about 5 miles down the road. It was still idling rough, But not as bad and I think I have the timing chain death rattle that I have been reading about. But the Check Engine like did not come on till I got back home and parked it while idling. The new codes are the same as above plus

P0300(Random/Multiple Cylinder Misfire)

What Else should I try to do to get this engine to idle right. I runs fine on the highway and Has plenty of pick up and go. Its just the idle pretty much shakes the whole Vehicle. Can anybody pin point some things I should look at instead to just tossing money at it, Would running seafoam through it help any?

Thanks,
John
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
LIGHT TRUCK: 1996-1998 EXPLORER
1997-1998 MOUNTAINEER


This TSB article is being republished in its entirety to revise the Issue and Action.

ISSUE:
On engines built prior to January 5, 1998, the Malfunction Indicator Lamp (MIL) may illuminate and Diagnostic Trouble Codes (DTCs) P0171, P0174, P1131, and/or P1151 may be present with or without driveability symptoms such as misfire, rolling idle, rough idle, etc. This may be caused by the lower plenum-to-cylinder head O-rings.

ACTION:
Inspect for shrinking/collapsing O-rings that will create a lean condition, usually when the engine is operating cold. The O-rings may also be damaged from a previous engine repair where they may "fold." When the O-ring shrinks/folds, it will allow a very small amount of unmetered air to pass through. Refer to the appropriate year Powertrain Control/Emissions Diagnosis (PC/ED) Service Manual for DTC diagnosis and the following Service Procedure for details.

SERVICE PROCEDURE

If the Heated Exhaust Gas Oxygen (HEGO) sensor is still targeted as the root cause, go to Step 2.
Using the New Generation Star (NGS) Tester, monitor the long fuel vs. short fuel trim Parameter Identification Displays (PIDs) with the engine cold.
If a large increase + to - is noted, introduce propane around the lower intake manifold O-rings.
If the difference between the two PIDs then decrease, the concern may be with the Lower Intake Manifold O-ring (F77Z-9461-BA). The Upper Intake Manifold Gasket (F77Z-9E436-AA) must also be replaced as part of this repair. Refer to the appropriate model year Explorer/Mountaineer Workshop Manual for details.

PART NUMBER PART NAME
F77Z-9461-BA Lower Intake Manifold O-Ring
F77Z-9E436-AA Upper Intake Manifold Gasket


OTHER APPLICABLE ARTICLES:
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
FORD: 1997-2000 EXPLORER, MOUNTAINEER


ISSUE:
A "knocking" noise at start up for up to 2 minutes from the left hand front chain cassette area may occur on some vehicles. After engine shutdown, the tensioner oil supply gallery empties. The noise may be due to air entering the left hand tensioner when the engine is restarted.

ACTION:
Replace the left hand camshaft tensioner with a revised Tensioner Kit. Refer to the Instruction Sheet within the Tensioner Kit for service procedure details.

WARNING: THE XU2Z-6K254-AA TENSIONER KIT IS FOR INSTALLATION ON THE LEFT SIDE OF THE ENGINE ONLY. INSTALLATION OF THIS KIT ON THE RIGHT SIDE OF THE ENGINE MAY RESULT IN ENGINE FAILURE. IF A TENSIONER IS NEEDED FOR THE RIGHT SIDE OF THE ENGINE, USE KIT XU3Z-6K254-BA.



PART NUMBER PART NAME
XU2Z-6K254-AA Tensioner Kit - Left Side
XU3Z-6K254-BA Tensioner Kit - Right Side



OTHER APPLICABLE ARTICLES:
 

sicktight722

Greatest man alive
Thanks Dave. I've been reading up on the 00M12 Kit and I'm going to get it this upcoming Friday and try to put it on this upcoming weekend. The kit pretty much addresses both things in your post, it has the O-rings/Gaskets for the upper and lower intake and the tensioner for the timing chain in the front of the engine ( I think) but not the tensioner for the other two timing chains. I actually did more this weekend to this explorer than I thought I would seeing how my wisdom teeth were pulled Friday morning. I've gotten the idle smoothed out a lot, but no way near perfect, so I hope this kit will help it some more.

Thanks again.YelloThumbUp
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
Correct the kit fixes both issues, the upper intake needs to be removed to install the tensioner, make sure you also install the restrictor in the oil passage it comes in the kit as well.
 

sicktight722

Greatest man alive
Still haven't got the kit yet, But started tearing things down getting it ready for next weekend. Well I got the lower intake manifold off and noticed a Puddle of bright green coolant sitting on top of the block at the front of the engine. There is also a plug in this area, that we found after we cleaned all the coolant out. My guess is the coolant is either coming from my head gasket, or that plug, my dad says the plug looks fine though. I have no oil in my coolant and no coolant in my oil, so how likely is it that the leak is coming from my head gasket? Would a pressure test show where it is coming from?
 

sicktight722

Greatest man alive
Never mind on the previous post. I believe the T-stat housing was leaking, So I'm upgrading it to the '02 housing on the Sport-trac. I believe it was leaking here as there was signs of a leak, and the pressure test showed nothing..
 

blacksnapon

Moderator
Staff member

sicktight722

Greatest man alive
so, new question.

Why does the 4.0L SOHC 4x4 in the explorers have balance shafts up to 2001? The 2001 ranger 4x4 with the same engine doesn't have a balance shaft, so is it really necessary? Meaning if I swap in a 01+ engine in my explorer 4x4 would it hurt anything my the engine now having the balance shaft?
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
so, new question.

Why does the 4.0L SOHC 4x4 in the explorers have balance shafts up to 2001? The 2001 ranger 4x4 with the same engine doesn't have a balance shaft, so is it really necessary? Meaning if I swap in a 01+ engine in my explorer 4x4 would it hurt anything my the engine now having the balance shaft?

This I really can't give you a right answer for but the way i've always understood it, it has something to do with the 4x4 in the explorers other than that you got me.
 

blacksnapon

Moderator
Staff member
The rangers do have a balance shaft in 01 (only in 4x4 models), the same as the explorers. This is a cut and paste from the 01 ranger workshop manual........ Engine
The 4.0L SOHC engine consists of the following:

single overhead camshafts
sequential multiport fuel injection (SFI)
distributorless ignition system
aluminum cylinder heads
cast iron, 60-degree V cylinder block
balance shaft (4x4 vehicles)
jackshaft
unique engine timing configuration
For quick identification, refer to the vehicle control information decal mounted under the hood
 

sicktight722

Greatest man alive
The rangers do have a balance shaft in 01 (only in 4x4 models), the same as the explorers. This is a cut and paste from the 01 ranger workshop manual........ Engine
The 4.0L SOHC engine consists of the following:

single overhead camshafts
sequential multiport fuel injection (SFI)
distributorless ignition system
aluminum cylinder heads
cast iron, 60-degree V cylinder block
balance shaft (4x4 vehicles)
jackshaft
unique engine timing configuration
For quick identification, refer to the vehicle control information decal mounted under the hood

hmm, i've read else where that the rangers 4x4 didn't have one, maybe i got the year wrong or just got bad info? Would it cause any long term problems putting a 2wd 4.0L SOHC engine without the balance shaft in a 4x4? The only thing I can find is that it will cause a slight vibration, but nothing about at what speed or if it will damage anything.
 

blacksnapon

Moderator
Staff member
Now, this is just a guess, but I believe because of the extra equipment (transfer case, driveshafts), the shafts are necessary because the extra loads will create an imbalance condition requiring a counter balance.
 

sicktight722

Greatest man alive
yeah, i'm reading on another forum and I can find nothing about adding the balance shaft, but a couple of ppl have actually took the chains off theirs. I also read that the balance shaft is really only there of low range 4wd? any truth to this?
 

sicktight722

Greatest man alive

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